The modern Olympic Games were first held in Athens, Greece, in 1896. They’ve been held every four years since – except in 1916, 1940 and 1944 due to the two world wars.
The numbers of events, countries and competing athletes have generally increased at each Olympiad, especially since the second world war.
About 10,500 athletes from more than 200 countries are competing at the Olympic Games in Rio.
Click on the buttons below to see how the numbers of events, countries and athletes have changed since 1896. Hover over the bar to view city and games detail.
The 1896 Athens Games had nine Olympic sport disciplines and 43 events. The 2016 Rio Games will have 42 disciplines and 306 events.
Athletics has always had the most events at the Olympics, from 12 in 1896 to 47 in Rio.
Faster, higher, stronger
No discipline epitomises the Olympic motto of citius, altius, fortius (faster, higher, stronger) better than athletics. Modern athletes are running times, jumping heights and throwing distances that would have seemed impossible in 1896.
But are today’s Olympic athletes the fastest, highest and strongest the world has ever seen?
Faster: 100m sprint
The current men’s gold medallist Usain Bolt won the final in London 2012 in a time of 9.63 seconds, an Olympic record. Bolt also holds the world record of 9.58 seconds, which he set in 2009.
While the women’s 100m event has generally become faster, Florence Griffith-Joyner set the Olympic record of 10.54 seconds 28 years at the 1988 Seoul Games. The current Olympic champion, Shelly-Ann Fraser of Jamaica, won in London in a time of 10.75 seconds.
Click on ‘Race simulation’ below to view all the Olympic gold medallists race each other. You can choose to simulate the men’s and women’s 100m race.
Higher: high jump
Like the women’s 100m sprint, recent Olympians have not beaten the current Olympic high jump record. The men’s record of 2.39 metres was set back in 1996 (Atlanta, USA). The women’s record was set in 2004 (Athens, Greece).
Stronger: the discus throw
Similarly, the Olympic record for the discuss throw has not been beaten in recent Olympics. The men’s record of 69.89 metres was set in 2004 and the world record of 74.08 metres was set back in 1986. The women’s Olympic record of 72.30 metres was set in 1988.
The changing bodies of athletes
Athletes today are generally taller and stronger than the first Olympians. But the degree of change depends on the type of event.
Modern sprinters tend to be more muscular than early Olympians, but not significantly taller. The average height and weight of middle- and long-distance runners have not change greatly over time. But athletes competing in strength events today are significantly taller and weigh considerably more than the first Olympians.
Doping and the Olympics
The International Olympic Committee (IOC) banned performance-enhancing drugs for the 1968 Games in Mexico City. The only athlete to be banned then was Swedish pentathlete Hans-Gunnar Liljenwall, who was stripped of his bronze medal for alcohol use.
Since then, more than 160 athletes have been banned for taking performance-enhancing drugs at the Olympics. This number could increase significantly as urine samples from past games are retested using more sophisticated processes.
The IOC recently announced that samples from 45 athletes from the 2008 and 2012 Games failed drug tests.
Athletics and weightlifting have the most banned athletes.
Authors: Reema Rattan, Series + Specials Editor, The Conversation