It's such a rare feat that only five players in golf's modern era have achieved the career grand slam of all four majors, yet three current players are on the brink of joining that lofty elite.
Jordan Spieth, Rory McIlroy and Phil Mickelson have each won three of the four big ones and are in a race to stand alongside Ben Hogan, Gene Sarazen, Jack Nicklaus, Gary Player and Tiger Woods as true legends of the game.
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Spieth can seal the slam with victory in the US PGA, McIlroy just needs the Masters and Mickelson is still searching for a US Open after six runner-up spots.
When Spieth won the Open in remarkable fashion at Royal Birkdale in 2017, he became the second youngest player after Nicklaus to win three different majors before his 24th birthday.
Victory in this year's US PGA would make Spieth the second youngest grand slam winner -- only Woods won all four before the age of 25. Spieth turned 25 on July 27.
CNN Sport takes a look at the five golfing greats who have completed a career grand slam in golf's Masters era. No one has yet won all four in a calendar year although Woods achieved the "Tiger Slam" -- holding all four majors across two calendar years (US Open, British Open, US PGA in 2000 and Masters in 2001).
Gene Sarazen (1935)
The great American amateur Bobby Jones clinched the big four of the day -- the British Amateur, British Open, US Open and US Amateur -- in 1930, but Gene Sarazen was the first player to achieve what would become known as the career grand slam.
The American, credited with inventing the modern sand wedge, dominated the 1922 season, winning the US Open and US PGA Championship in quick succession aged just 20.
It would, however, take a full decade for him to clinch the British Open. Sarazen took home the winner's share of £100 at the 67th Open Championship in 1932 -- the only time it was ever held at Prince's Golf Club in southeast England.
Sarazen completed the set at Augusta National in the second ever Masters in 1935 aged 33, emerging victorious thanks to a final-round double eagle at the par-five 15th now known as the "shot heard around the world."
He had been three shots off the lead until his albatross -- one of just four ever made at the Masters to this day -- and went on to win the 36-hole playoff with Craig Wood.
Ben Hogan (1953)
The American won the first of his nine majors at the age of 34 in 1946, but he nearly lost his life in a serious car crash three years later.
However, Hogan recovered to win his fourth major at the US Open in 1950, and conquered the career grand slam in 1953, winning the British Open at Carnoustie on the first and only occasion he entered.
That win was just part of a golden season for the 40-year-old Texan with the textbook swing. He also won the Masters and US Open and could have won of all four majors that year, had the British Open not clashed with the US PGA.
Still, his "Triple Crown" season has only been emulated once since, by Woods a full 47 years later.
Gary Player (1965)
Despite the achievements of Sarazen and Hogan, the modern notion of the "grand slam" was really popularized by Arnold Palmer in 1960.
The idea spread like wildfire, but Palmer -- a seven-time major winner -- was never able to secure the US PGA to complete the set, placing second on three occasions.
Instead, globe-trotting South African Gary Player sealed the deal when he won his fourth major, the US Open, in 1965 at the age of 29, six years on from his first.
Player's victory at Bellerive Country Club made him the first foreign-born winner of the US Open for 38 years.
The man known as the "Black Knight" added two more Masters, two more British Opens and a US PGA, but another US Open eluded him in his quest for a second grand slam. Player remains the only non-American to boast a career grand slam in golf.
Jack Nicklaus (1966)
Jack Nicklaus joined the grand slam club aged 26 -- two years older than Woods -- when he won the 1966 British Open at Muirfield.
He might have done so even earlier.
The Golden Bear was midway through his 24th year when he won his third major at the 1963 PGA Championship. It took him another three years to add the final piece of the puzzle.
Not that he let up. Nicklaus, a record 18-time major winner, accomplished the "double" career grand slam in 1971 and the "triple" just seven years later.
The last three of his majors were secured over the age of 40, and his final title -- the 1986 Masters -- at 46.
Tiger Woods (2000)
Woods is the youngest player in history to have achieved the career grand slam.
The American made his major breakthrough at the Masters in 1997, added the US PGA in 1999 and clinched the US Open and British Open at St Andrews in 2000 at the age of 24.
Woods also won the US PGA that year to complete the "Triple Crown."
He is the only other player alongside Nicklaus to win all four majors at least three times over the course of his career.
He secured a second grand slam at the 2005 British Open back at St Andrews and a third with the latest of his 14 major wins at the 2008 US Open.