The Basilica di San Marco (St. Mark's Church) is the most improtant church in Venice and is the adorning monument of the Piazza San Marco (St. Mark's Square). As you can see from the picture below, the gilded domes of the church's interior are the finest examples of Byzantine mosaics in western Europe. The church was originally built in 823 as a chapel adjacent to the Doge's palace, but was rebuilt in its current form in 1094. Sadly, like most of Venice, the building is deteriorating and you can see from the cracks and waves in the floor that the building is sinking into the ocean.