St. Mark's Basilica is a famous church located in Venice, Italy. Known for its stunning architecture and intricate mosaics, it serves as the cathedral of the Roman Catholic Archdiocese of Venice. The basilica was originally built in the 9th century and has undergone several renovations over the years. The church is named after Saint Mark, the patron saint of Venice, whose relics are believed to be housed within. Its unique blend of Byzantine and Romanesque styles attracts millions of visitors each year, making it one of the most iconic landmarks in the city.