10 of the great heavyweight boxers of all time

Many notable heavyweight boxers throughout history have held the title of "baddest man on the planet." After all, the men who have populated this division are often some of the most intimidating, powerful, and charismatic athletes ever. Boxing has as rich a history as any other sport, but as in most professions, some truly set themselves apart as some of the greats.

Although boxing is one of the world's oldest sports, it underwent many changes before becoming what it is today. Upwards of twenty, thirty, or even forty rounds were standard in the days of loosely codified and taboo bare-knuckle brawls.

However, popular fighters like "Gentleman" Jim Corbett (11-4-3) helped usher in the new era of heavyweights, and the sport has flourished ever since Corbett defeated the last recognized bare-knuckle champion John L. Sullivan (47-1-2) in 1892.

Corbett revolutionized boxing inside and out. He developed new training regimens and focused on technique. His losing battles with fellow legend James J. Jeffries (19-1-2) in 1900 and 1903 brought boxing to a whole new audience thanks to new motion picture technology only just being pioneered at the time.

Heavyweight history stomped on from there, producing iconic moments and personalities who continued pushing the sport in new ways. Heavyweights remain popular through their blistering knockouts and often mega-size personalities. Many fantastic heavyweights have competed, so compiling a list of only 10 is challenging.

Factors taken into account for this countdown are legacy, accomplishments, records, and finally each boxer's respective era. Training regimens and fight schedules have evolved since the sweet science's early days and this list will attempt to give each athlete their due, regardless of the timeframe they competed in.

Here are 10 of the great heavyweight boxers any well-versed fan of pugilism must know about.

10. Oleksandr Usyk

Oleksandr Usyk (22-0) perhaps represents the best of what the current generation of heavyweight boxing has to offer. Defeating two of his contemporaries Anthony Joshua (28-3) and Tyson Fury (34-1-1) only solidifies Usyk's claim as the top dog.

The 37-year-old Ukrainian Usyk unified the heavyweight crown of each of the four major boxing-sanctioning bodies including the World Boxing Association, World Boxing Council, International Boxing Federation, and World Boxing Organization.

Usyk has had a remarkable professional career, but his amateur career was ridiculous. His record of 335-15 was a foretaste of the dominance he'd display once turning pro in 2013. Usyk's most prestigious amateur accomplishment was a gold medal in the heavyweight class during the 2012 London Olympics.

Many powerful men have dominated the heavyweight boxing scene in recent history, but Usyk's accomplishments set him apart. Defeating Joshua and Fury and thus collecting their titles made Usyk the first undisputed heavyweight champion of the current four-belt era.

Usyk's blistering southpaw style has also earned him success as a cruiserweight, making him a rare fighter in that he's held undisputed gold in two weight classes. The 6 foot 3 inch Usyk has earned 14 career knockouts but is also as technical as they come, truly outboxing the fundamentally sound Fury en route to his split decision victory.

Dethroning two of the finest heavyweights of this generation proves what a beast Usyk truly is. It remains to be seen how much further he propels his legacy and whether or not he can defeat the ultra-talented Fury once more. Usyk's accomplishments thus far however thrust him into rare company and make him one of the great heavyweight boxers.

9. Jack Dempsey

Jack Dempsey (69-6-9) was a cultural hero of the 1920s, inspiring all the great heavyweight power punchers to come. He was perhaps an undersized heavyweight by modern standards, standing only 6 feet 1 inch tall and weighing in the neighborhood of 187 pounds, but his strength, toughness, and star power made him an icon.

53 career knockouts made Dempsey the preeminent knockout artist of his generation. His aggressive style earned him the world heavyweight title in 1919 and he held the crown till 1926, losing to fellow icon Gene Tunney (79-1-4). Dempsey's overall career stretched from 1914-1927

Dempsey's influence was felt everywhere. He popularized boxing in all new ways, selling out stadiums and setting records. He helped pioneer live sports broadcasts as boxing fans everywhere tuned into radios to hear his exploits. This set the groundwork for boxing to be one of the twentieth century's most popular spectator sports along with baseball and horse racing.

Bobbing, weaving, and swinging heavy leather were trademark Dempsey and would come to inform how many other fighters would develop their styles in the years to come. He honed his skill by challenging grown men to barroom brawls for cash while still only a teenager. There, he grew comfortable with often being the undersized fighter, compensating for his lack of physicality with aggression and power.

Dempsey only lost one fight via knockout and that was to "Fireman" Jim Flynn (76-46-22) but later avenged himself with a knockout victory of his own. After defeating one of the best heavyweights of his time, the imposing 6 foot 6 inch tall champion, Jess Willard (25-7-2), Dempsey asserted his legend.

He defended his title five times till losing to Tunney twice (the second time in the controversial "Long count fight") and then retiring.

8. Joe Frazier

Perhaps the best left hook in boxing history belonged to Joe Frazier (32-4-1) who used that, along with tremendous skill in almost every facet of the game to earn 27 knockouts through the 1960s and 70s. His legendary bouts and rivalries with other top fighters of his era including Muhammad Ali (56-5) and George Foreman (76-5) helped push boxing even further into the collective subconscious.

Heavyweight boxers come in all shapes and sizes. However, the 5 foot 11 inch tall Frazier dominated some of the big men of his time with technique and poise. Frazier was a thinking man's fighter, training boxers in his Philadelphia gym post-retirement and even releasing one of the preeminent books on boxing technique, Box Like the Pros.

Frazier got into boxing as a young man, hanging makeshift heavy bags around his family's property and walloping them each day, developing the knockout power he'd come to be known for as a professional.

An amateur record of 38-2, numerous gold glove titles, and a gold medal in the 1964 Olympics thrust Frazier toward a professional career. He made his debut in 1965 and by 1970 won the heavyweight title by stopping Jimmy Ellis (40-12-1) for the vacant crown. The only thing Frazier needed to solidify himself as the best was a win over the former lineal champ, Ali.

Frazier made good on his chance, defeating Ali in 1971 at the famous Madison Square Garden. Frazier controlled much of the highly competitive contest, even knocking Ali down at one point in what was billed as the "Fight of the Century."

Though Frazier slightly faltered afterward, losing the title to Foreman and then losing rematches to Ali, he only ever succumbed to the best boxers at the time.

7. Lennox Lewis

Lennox Lewis (41-2-1) is one of the largest, most imposing, and most successful heavyweight boxers in history. Standing 6 feet 5 inches tall and winging an 84-inch reach, Lewis was a force in the ring, accumulating 32 knockout victories and avenged the only two professional losses on his resume to Oliver McCall (59-14)(2) and Hasim Rahman (50-9-1)(2) respectively.

Lewis defeated some of the most feared fighters of his time including Mike Tyson (50-6)(2) and Evander Holyfield (44-10-2)(1).

Being a star athlete made it possible for Lewis to pursue any sport he set his sights on. Luckily for boxing fans, his desire to compete in the ring won out and saw him earn tremendous amateur success. He won a gold medal in the 1988 summer Olympics after repeatedly attempting and failing to earn his oportunity.

Once Lewis accomplished his dream of being an Olympic champion, he set his sights on pro boxing and spent the years between 1989 and 2003 terrorizing the big men of that time. He earned the heavyweight title three times and beat all the major stars boxing offered.

Lewis holds dual Canadian and British citizenship and has influenced numerous stars from both nations. His impact and dominance are still felt, as his heavy jab set the foundation for some of the titanic heavyweights that followed.

6. Jack Johnson

Jack Johnson (73-13-10) is not only one of the most important boxers in history but perhaps one of the most important athletes ever. As the first black world heavyweight champion, Johnson inspired numerous African Americans to pursue prizefighting and sport. His star power made him one of the most famous, albeit controversial sports figures in the early twentieth century.

Johnson cut his teeth in boxing at a time when prizefighting was still illegal in most states. His career spanned from 1897 to 1928. He held heavyweight titles among segregated boxing associations but was allowed to challenge for and eventually earn the world heavyweight title, a crown he held from 1908-1915. He defeated Jeffries for the belt, the aforementioned pioneer of boxing as it's come to be known

Racial animosity came to define much of Johnson's reign, as white boxers and fans refused to believe an African American fighter was as dominant as his success proved. Race riots, ignited by his success and victory over Jeffries in the first "Fight of the Century" prompted bans on films of his exploits.

34 career knockouts and a dominant championship run however asserted his legend. After losing his title to Willard (the man later defeated by Dempsey) Johnson continued taking fights and his popularity never dipped. Though he lost more as he exited his prime, Johnson was known for his tremendous defense, power, and personality.

5. Rocky Marciano

Rocky Marciano's (49-0) imposing heavyweight resume has stood the test of time. His skill, chin, and knockout prowess defined the late 1940s and early 1950s. His 43 career knockouts, undefeated status, and six title defenses helped set standards for greatness most fighters could only hope to emulate.

Marciano was a solid athlete, even before setting his sights on professional boxing. His baseball talent saw him try for a spot with a farm team for the Chicago Cubs, but after being cut he focused on boxing.

After serving in the U.S. Army during World War II and winning boxing tournaments within the armed forces, Marciano went pro in 1947 and captured the heavyweight title in 1952 by defeating Jersey Joe Walcott (49-20-1). His title opportunity was partially set up by a 1951 TKO victory over the legendary Joe Louis (66-3) that set the stage for Marciano's incoming status as a household name in the world of boxing.

Marciano's signature Suzie Q right cross was one of boxing's most feared weapons. He flatlined numerous opponents with that strike, asserting himself as the 1950s greatest knockout technician. Marciano's final knockout victory came against fellow legend and light heavyweight champion Archie Moore (186-23-10) in 1955, allowing him to retire with an unblemished pro record.

4. George Foreman

Heavyweight boxing history is filled with intimidating punchers, but Foreman (76-5) is one fighter who stands out like no other. After taking a hiatus from professional fighting, Foreman made a comeback and at 45 years old became the oldest heavyweight boxing champion in history. His 68 career knockouts account for more wins than many fighters achieve in their entire careers. Foreman is notable for helping set the standard for what it truly meant to have "heavy hands."

As is the case for many of the fighters recognized in this list, Foreman set the stage for his tremendous professional career by dominating the amateur ranks. He earned gold in the 1968 Olympic Games in the heavyweight division, stopping older and more seasoned fighters along the way thanks to his bruising onslaught of power shots.

After turning pro in 1969, Foreman won his first heavyweight title in 1973 by knocking out Frazier in only the second round. His reign was somewhat short-lived, losing the belt to Ali in 1974's famous "Rumble in the Jungle" by eighth-round knockout. Mixed success from then on as well as an inability to coax Ali into a rematch saw Foreman take a break from fighting after a 1977 loss to Jimmy Young (35-18-3).

After indulging a life away from combat, Foreman returned to the ring in 1987 and competed for another decade, capturing the heavyweight title again along the way. Foreman's 6 foot 4 inch frame and 79-inch reach accounted for some of the terrifying power he unleashed upon opponents during his active stretches.

Dominance through his prime and arguably past it asserts Foreman as one of the greatest heavyweight boxers ever and an inspiration to many who pursued the sport after.

3. Mike Tyson

Being an ever-present pop culture figure and one of the most feared boxers of all time asserts Tyson (50-6)(2) as one of the great heavyweight boxers to ever lace on a pair of gloves. Few have ever possessed the aura or intimidating ability Tyson did when he collected chins throughout his prime.

Tyson holds the distinction as the youngest boxer to win a heavyweight title, doing so at only 20. Tyson's fights became appointment viewing for boxing fans in the late 1980s, as he carved through some of the sport's finest athletes with 24 first-round knockouts throughout his career.

His first title reign lasted from 1987-1990 and regained the belt in 1996, becoming one of the few boxers to get back to the gold after losing it the first time.

44 career overall knockouts make Tyson one of the most powerful punchers in recent history. His aggressive style saw him bob and weave into range and throw short, explosive hooks and uppercuts to stun opponents, sending them crashing to the canvas.

Tyson remains influential, both inside and outside professional boxing circles. He's looked at as a punching guru and has competed sporadically in exhibition matches since his last professional contest in 2005.

2. Muhammad Ali

Ali (56-5) is a figure who transcended professional boxing, known for his smooth trash talk and incredible in-ring talent. Ali is not only one of the greatest heavyweight boxers ever but is shortlisted on many countdowns for greatest overall boxer of all time. His rivalries and triumphs over contemporary greats like Frazier, Foreman, and Sonny Liston (50-4) make Ali one of the best fighters to rise out of the 1960s and 70s.

Effortless movement, stinging attacks, and mind games characterized much of Ali's career. His 1960 Olympic boxing gold medal primed him for a pro career that spanned from late 1960 till 1981.

Ali was one of the youngest champions of his time, earning the title at 22 years old by defeating Liston in 1964. Though Ali was stripped of his title for opposing the Vietnam War in 1967, he regained the belt as a heavy underdog by defeating Foreman in 1974.

With his legacy set, Ali stuck around and defended the title 10 more times before succumbing to Leon Spinks (26-17-3) in back-to-back contests and never finding a path back toward true championship contention. However, Ali dispatched nearly every great fighter competing in his era and asserted himself not only as one of the most important boxers ever but also as a defining figure of the twentieth century.

1. Joe Louis

Louis (66-3) is one of the most important heavyweight boxers of all time as well as one of the greatest. His 25 consecutive title defenses and reign lasting from 1937-1949 is a record yet to be approached by any boxer. 52 career knockouts set Louis as one of the most feared strikers to compete in professional boxing. He became an African American sports hero before the notion of one even existing crossed the collective minds of people living in that period.

Earning a reputation not only as a fantastic boxer, but a humble sportsman and national hero at a time when these tasks seemed insurmountable helped Louis set himself apart in the annals of great boxers. He paved the way for most of the men on this list, regardless of race or creed.

Louis defeated James J. Braddock (52-26-7) in 1937 for the heavyweight title and avenged his only career loss to that point against Nazi Germany's Max Schmeling (56-10-4) in a heavily promoted bout that captured the attention of the world at a time when tensions were mounting toward another global conflict.

Losing his crown to Ezzard Charles (95-25-1) in 1950 proved to be a great setback for Louis as despite winning his next eight fights he never regained the strap and lost his final bout to Marciano. But, by that point, his long reign, iconic status, and presence as a national sports hero solidified Louis not only as one of the greatest athletes of the time but also as one of the greatest heavyweight boxers to compete in history.