<Ul> <Li> IOC </Li> <Li> HOC </Li> <Li> ATHOC </Li> </Ul> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> The 2004 Summer Olympic Games (Greek: Θερινοί Ολυμπιακοί Αγώνες 2004, Therinoí Olympiakoí Agó̱nes 2004), officially known as the Games of the XXVIII Olympiad and commonly known as Athens 2004, was a premier international multi-sport event held in Athens, Greece, from 13 to 29 August 2004 with the motto Welcome Home . 10,625 athletes competed, some 600 more than expected, accompanied by 5,501 team officials from 201 countries . There were 301 medal events in 28 different sports . Athens 2004 marked the first time since the 1996 Summer Olympics that all countries with a National Olympic Committee were in attendance . 2004 also marked the return of the games to the city where they began . </P> <P> A new medal obverse was introduced at these Games, replacing the design by Giuseppe Cassioli that had been used since the 1928 Games . This rectified the long lasting mistake of using a depiction of the Roman Colosseum rather than a Greek venue . The new design features the Panathenaic Stadium . The 2004 summer games were hailed as "unforgettable, dream games" by IOC President Jacques Rogge, and left Athens with a significantly improved infrastructure, including a new airport, ring road, and subway system . The cost of the 2004 Athens Summer Games has been cited as a contributor to the Greek government - debt crisis . Some of the venues lie vacant and rotting, while others are in use; the ones at the Olympic Park and others in the coastal area are in regular use . </P>

What is the host nation of the 2004 summer olympic games