The 2004 Summer Olympics, officially the Games of the XXVIII Olympiad and also known as Athens 2004, were an international multi-sport event held from 13 to 29 August 2004 in Athens, Greece. The Games saw 10,625 athletes compete, some 600 more than expected, accompanied by 5,501 team officials from 201 countries, with 301 medal events in 28 different sports. The 2004 Games marked the first time since the 1996 Summer Olympics that all countries with a National Olympic Committee were in attendance, and also marked the first time Athens hosted the Games since their first modern incarnation in 1896 as well as the return of the Olympic games to its birthplace. Athens became one of only four cities at the time to have hosted the Summer Olympic Games on two occasions. A new medal obverse was introduced at these Games, replacing the design by Giuseppe Cassioli that had been used since 1928. The new design features the Panathenaic Stadium in Athens rectifying the long-running mistake of using a depiction of the Roman Colosseum rather than a Greek venue. The 2004 Games was the first of two consecutive Olympic games to be held in Southern Europe since the 1992 Summer Olympics in Barcelona, Spain, and was followed by the 2006 Winter Olympics in Turin, Italy.

Athens is the capital and largest city of Greece. A major coastal urban area in the Mediterranean, Athens is also the capital of the Attica region and is the southernmost capital on the European mainland. With its urban area's population numbering over three million, it is the eighth largest urban area in the European Union. The Municipality of Athens, which constitutes a small administrative unit of the entire urban area, had a population of 643,452 (2021) within its official limits, and a land area of 38.96 km2 (15.04 sq mi).