has it been used for any other purpose?
Yes, hosted the opening ceremony of the 1997 World Championships in Athletics
Panathenaic Stadium
The stadium hosted the opening ceremony of the 1997 World Championships in Athletics on a concept by composer Vangelis and along with the performance of soprano Montserrat Caballé.

In more recent years, the stadium has been often used to honour the homecoming of victorious Greek athletes, most notably the Greece national football team after its victory at the UEFA Euro 2004 on 5 July 2004 as well as Greek medalists in recent Olympic Games.
who took part in the modern olympic games Fourteen nations; all European, and 241 athletes (all males) when was this? From 6 to 15 April 1896 where did it take place? Athens, Greece which were the venues? Panathenaic Stadium, Marathon, Bay of Zea, Zappeion, Kallithea, and Athens Lawn Tennis Club was there an opening ceremony conducted? Yes where? Panathenaic Stadium
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Panathenaic Stadium [SEP] Other events
The stadium hosted the opening ceremony of the 1997 World Championships in Athletics on a concept by composer Vangelis and along with the performance of soprano Montserrat Caballé. In more recent years, the stadium has been often used to honour the homecoming of victorious Greek athletes, most notably the Greece national football team after its victory at the UEFA Euro 2004 on 5 July 2004 as well as Greek medalists in recent Olympic Games.