Every Olympics produces at least a couple of nail-biting finishes, races so close we yell ourselves hoarse screaming at the television, as if that would push the athletes just a little bit harder. The Games are like that. The very best athletes in the world push themselves beyond anything we can comprehend in races decided by hundredths of a second or fractions of an inch. Who can forget the breathtaking finish of the men's 100-meter butterfly in Beijing, where Michael Phelps beat Milorad Cavic by a mere 4.7 millimeters? Moments like that are why we tune in. The job of measuring finishes that close falls to the Olympic timers, a team of 450 technicians who use more than 400 tons of equipment to ensure peerless accuracy timing. But sometimes even the very finest in timing technology is not enough, as we saw during the women's 100-meters trials in June, when Jeneba Tarmoh finished in a dead heat against Allyson Felix. Dead heats are rare, but not unheard of, as we saw during the 1984 Summer Games when Nancy Hogshead and Carrie Steinseifer registered the same time in the 100-meter freestyle. Both won gold, the first double-gold in swimming history. Close finishes are what give the Games their excitement. Here, straight from The Book of Olympic Lists: A Treasure-Trove of 116 Years of Olympic Trivia (Aurum Press, $14.95) by David Wallechinsky and Jaime Loucky, are 10 incredibly close Olympic finishes. Above: 100-meter Freestyle Swimming, 1960 Lance Larson (Lane 4) of the United States and John Devitt of Australia (Lane 3) finished in a near dead heat. Devitt congratulated Larson and left the pool in disappointment. Confusion developed, however, when the judges met to discuss their verdict. Of the three judges assigned to determine who had finished first, two voted for Devitt and one for Larson. However, the second-place judges also voted 2–1 for Devitt. In other words, of the six judges involved, three thought Devitt had won and three thought Larson had won. When the electronic timers were consulted, it turned out that Larson had registered 55.1 seconds and Devitt 55.2. The unofficial electronic timer also showed Larson winning—by four inches, 55.10 to 55.16. Despite this evidence, the chief judge, Hans Runströmer of Germany, who did not have any say in the matter according to the official rules, ordered Larson’s time changed to 55.2 and gave the decision to Devitt. Four years of protests failed to change the result. Photo: AFP/Getty Images

Cycling Road Race, 1964 Held over 194 kilometers (120 miles), the 1964 road race saw a spectacular finish in which Mario Zanin, (right) a mechanic from Italy, emerged from the pack with 20 meters to go and won by a wheel. The finish was so close that Sture Pettersson of Sweden crossed the line only sixteen-hundredths of a second behind Zanin, yet he ended up in 52nd place. Photo: AP

100-meter Freestyle Swimming, 1964 A minor controversy developed over the award of the bronze medal in the 100-meter freestyle. The judges were split as to whether American Gary Ilman or German Hans-Joachim Klein (pictured on the third step) had finished third. Both were clocked in the same time. The Japanese had thoughtfully provided electronic timers for the swimming events and, even though they were not used officially, they were consulted by the judges. It turned out that Ilman and Klein had stopped the clock at exactly the same hundredth of a second, but that Klein had finished one one-thousandth of a second sooner. After 35 minutes of consultation, the judges decided that, even if the electronic timing was unofficial, it had provided sufficient cause to award third place to Klein. Photo: Keystone/Getty Images

Women’s Pentathlon, 1976 With four events finished and only the 200 meters to be run, the top eight competitors were separated by only 95 points. All the leaders were matched against one another in the final heat. When the dust cleared 26 seconds later, officials and fans hurriedly consulted their scoring tables. It was discovered that Siegrun Siegl of East Germany, the world record holder in the long jump, and Christine Laser, also of East Germany, had finished with the exact same points total, while another East German, Burglinde Pollak, was only five points behind. Siegl was finally awarded first place, on the basis of having beaten Laser in three of the five events. Had Pollak run six hundredths of a second faster she would have won the gold medal. Instead she had to settle for her second straight bronze. While Siegl jumped from seventh to first in one event, Nadezhda Tkachenko of the Soviet Union had the misfortune of dropping from first to fifth in less than 25 seconds. Video: olimpsportas/YouTube

Women’s 100-meter Freestyle, 1984 After the 1972 Larsson-McKee incident (see 4. above), it was decided that because of possible technical problems, hundredths of a second would have to do in future events instead of thousandths. So in 1984, when Nancy Hogshead and Carrie Steinseifer, both from the United States, registered the same time of 55.92 in the 100-meter freestyle, a dead heat was declared, and each was awarded a gold medal—the first double gold medal in Olympic swimming history. Photo: Tony Duffy/Getty Images

Kayak Singles 1,000-meter Canoeing, 1988 Greg Barton was a mechanical engineer who grew up in Homer, Michigan, a small town with more pigs than humans. In Seoul, Barton and Australia’s Grant Davies crossed the finish line in a near dead heat. Barton was told by South Korean officials that he had won. Then the scoreboard flashed the news that Davies was the victor. While the Australians celebrated and Barton prepared for the final of the 1,000-meter pairs, the jury of the International Canoe Federation examined the finish-line photo. A few minutes later they announced that Barton had won by .005 seconds — less than 1 centimeter. Greg Barton had become the first US kayaker to win an Olympic gold medal. Davies was stoic. “If that’s the biggest disappointment in my life,” he said, “I can handle it.” Photo: Lionel Cironneau/AP

100-meter Butterfly, 1988 Favorite Matt Biondi of the U.S. led from the start. Ten meters from the finish, he was still in first place by 2 feet. But as he neared the touch pad he was caught between strokes and elected to kick in the last few feet instead of taking an extra stroke. However, he was farther away than he thought, and his miscalculation allowed 20-year-old Anthony Nesty of Suriname (shown celebrating his win) to slip by and win by less than an inch. After the race Biondi mused, “One one-hundredth of a second—what if I had grown my fingernails longer?” He successfully channeled his disappointment and went on to win five gold medals. Photo: Richard Mackson /Sports Illustrated/Getty Images

Women’s 100 Meters, 1992 The 100-meter final in Barcelona was the closest track race in Olympic history. Gail Devers (Lane 2) of the United States and Irina Privalova of Russia (Lane 6) ran almost even most of the race, but Jamaicans Julie Cuthbert (Lane 3) and Merlene Ottey and American Gwen Torrence all came on at the end. It was impossible to tell who had won until slow-motion replays of the finish were shown in the stadium. Even then, one couldn’t be sure. The official announcement finally gave the victory to Devers. Ottey ended up in fifth place, even though she was less than one-tenth of a second behind the winner. Photo: Manny Millan/Sports Illustrated/Getty Images

100-meter Butterfly, 2008 The 100-meter butterfly was the only race Michael Phelps swam at the 2008 Olympics for which he did not already hold the world record. American-born Milorad Cavic, competing for Serbia, set an Olympic record in the first round and led the field halfway through the final, with Phelps trailing in seventh place. In a sensational finish, Phelps surged over the final 50 meters, making up a deficit of more than half a second to touch in a virtual tie with Cavic that was too close to call by the naked eye. The results of swimming races are now determined not by a photo, but by the pressure applied to touch pads. Omega, the official timekeeper of the Olympics (and one of Phelps’ sponsors) announced that Phelps had won by 4.7 millimeters (one-sixth of an inch). Photo: Mark J. Terrill/AP

400-meter Individual Medley, 1972 Sweden’s Gunnar Larsson and Tim McKee of the U.S. were both credited with the Olympic record, but Larsson was declared the winner by two thousandths of a second, 4:31.981 to 4:31.983. As a result of this race, the rules were changed to declare a dead heat in any swimming contest in which the swimmers were tied to hundredths of a second, although this rule was later changed. Photo: Keystone-France/Gamma-Keystone via Getty Images