Major League Baseball is a professional North American baseball league. It is also regarded as the world's best professional baseball. Two leagues comprise the MLB: the American League, also known as AL, and the National League, also known as NL. At present, there are thirty MLB clubs, 29 from the United States, and the Toronto Blue Jays are the only ones coming from Canada.

In 1876 and 1901, both the NL and the AL were created. The two leagues cooperated from 1903 until 2000 when they united into the same association headed by the Baseball Commissioner but remained legal independent bodies.

Some MLB records can be seen as "unbreakable" due to either random events or the fact that they were established in the early decades of baseball when there were different rules. Others are caused by changes in the game over time which makes it impossible for the records to be broken.

Fans cheer during the sixth inning between the Baltimore Orioles and St. Louis Cardinals in 2011. (Getty)

Who holds the record for most MLB career wins?

Cy Young holds the record for the most career wins with 511, for his triumphs from 1890 to 1911. His accomplishments include five seasons of 30 wins and 15 seasons of 20 wins. Walter Johnson with 417 is the next nearest player, and he is the only other player with 400 wins.

Denton True "Cy" Young was an American baseball player. During his 22 years in Major League Baseball (MLB), he set a number of milestones, some of which lasted for 100 years. The Cy Young Award was established by the MLB in 1956. The award is awarded yearly to the most efficient pitcher voted in the two leagues.

Walter Perry Johnson, meanwhile, spent all of his 21-year MLB career featuring for the Washington Senators. From 1929 to 1932 he was the Senators manager. He was called "the Big Train," as he was able to easily throw big shots at high speed. His fastball was the principal reason that he could do so well since he had the most 3,509 career strikes and shutouts ever. He was voted the American League Most Valuable Player twice, in 1913 and 1924.