Which famous building was the result of an international competition?

Here is the question :

WHICH FAMOUS BUILDING WAS THE RESULT OF AN INTERNATIONAL COMPETITION?

Here is the option for the question :

Sydney Opera House
Empire State Building
Big Ben
Hagia Sophia

The Answer:

And, the answer for the the question is :

Sydney Opera House

Explanation:

[STC0019963]. When the invitation for a new opera house in Sydney Harbour was issued in 1956, hundreds of architects responded. Jrn Utzon of Denmark won the award, receiving 5000 for his winning design, which resembled white boat sails placed against the harbour.