With the dominance of the "Big Four" showing signs of fraying in men's tennis, this year's Wimbledon could be the most unpredictable in years.

Only Roger Federer, Rafael Nadal, Novak Djokovic and Andy Murray have won on the grass of southwest London since 2002.

For many, winning Wimbledon is the pinnacle of the sport. Very few of the greats have not triumphed at the All England Club, perhaps only Ivan Lendl in the modern era.

Spencer Gore, who won the inaugural Wimbledon in 1877, was the man who supposedly introduced the serve-and-volley. His three-set victory over William Marshall took only 48 minutes.

British players, notably seven-time winner William Renshaw, won the first 30 titles. New Zealand's Anthony Wilding later won four straight titles from 1910-13.

After World War I, Wimbledon's international reach was evident, most notably with the success of French players in the 1920s, such as Rene Lacoste, Jean Borotra and Henri Cochet.

In 1938, Don Budge of the United States became the first player, male or female, to win the Grand Slam of all four major titles. But Australians soon took over as the ones to beat after World War II.

Between 1956 and 1971, Australian players won the Wimbledon title 13 times.

Perhaps the best of them was Rod Laver, who won his third Wimbledon title in 1968 as the Open era started — six years after he turned professional and wasn't allowed to compete in Grand Slam tournaments.

Since then, Wimbledon has had colorful characters and great rivalries, such as Bjorn Borg's battles with John McEnroe in the early 1980s, the athletic prowess of the Boris Becker-Stefan Edberg duels and Pete Sampras' dominance of the 1990s.

Sampras won seven titles, equaling the mark that Renshaw had set back in 1889. Federer joined then in 2012 and is still looking for No. 8.

The Associated Press has been covering Wimbledon for decades. Attached are some of the great champions as captured by photographers from the AP.