The gruelling three-week-long Tour de France bicycle race has always included mountain stages, though not as hard or as long as the mountain stages of today. (The first time the race went across the mountains, some riders claimed it was impossible, and called the organizers murderers.) Since the beginning there was an unofficial King of the Mountains, and that was the rider who reached the top of the peaks first. In 1933 the classification was first calculated, and the following year King of the Mountains became an offical calculation and title.
Spanish rider Vicente Trueba was the first to reach all the major peaks in that first year 1933, even the dreaded Tourmalet. Trueba was a great climber but a bad descender, and whatever he gained going up he lost going down. Therefore, when the classification was calculated, organizers decided that the first to reach the summit would get a time bonus equal to the gap between himself and the second rider, up to a maximum of two minutes. Today these time bonuses don't exist anymore, and riders win King of the Mountains based on points.
These days all climbs are ranked according to difficulty, from hors catégorie for the most difficult down to first, second, third and fourth category for the easier ones. The first fifteen riders over a hors catégorie peak gain points ranging from 40 for the first to 1 for the fifteenth; the first twelve over a first category peak get from 30 to 1; the first ten over a second category hill get from 20 to 1; the first five over a third category hill, 10 to 1; and the first three over the fourth category get 5, 3, and 1 points respectively.
As the overall points winner gets a green jersey and the overall time winner gets a yellow jersey, in 1973 race organizers introduced the red on white background polka-dot jersey for the King of the Mountains to wear. Eddy Merckx, incredibly, held the yellow, green, and polka-dot jerseys at the end of the Tour in 1969, the only rider ever to have accomplished such a feat. Federico Bahamontès and Lucien Van Impe have worn it six times at the end of the Tour, but Richard Virenque holds the record: seven polka-dot jerseys.