Over 100 palaces of the Russian nobility and a great many cathedrals and unique churches built by the greatest architects of the time still remain in Saint Petersburg. Most of them are open to the public now. Saint Petersburg is famous for its "white nights" - a period when there is as much light during night time as during the day time and many bridges are raised, so that numerous strolling romantics can enjoy the sight of ships passing down the Neva river city waterway all night long. The city has recently undergone an extensive renovation in celebration of its 300th anniversary in 2003. More than 80 museums and 40 theatres of St. Petersburg ensure that art, ballet, music, and theatre lovers will find the metropolis an endless source of cultural enjoyment.