Vladislav Zolotov/

The Catherine Palace in Tsarskoye Selo, about 15 miles south of St. Petersburg, served as the summer residence for the Russian tsars. Built in the 18th century in the Rococo style, it is a work of art inside and out, with opulently decorated halls, galleries and ballrooms and an ostentatious exterior; about 220 pounds of gold were used in its façade and in multiple statues on the roof.