Simplify the following text for a Grade 11 native English-speaking person.
Original: The Helsinki Olympic Stadium , located in the TÃ Ã lÃ district about 2 k from the center of the Finnish capital Helsinki , is the largest stadium in the country , nowadays mainly used for hosting sports events and big concerts .
Simplified: Helsinki Olympic Stadium ( or Olympiastadion ) is a sports stadium located in the capital of Finland , Helsinki .