Russia's Peter the Great's first palace in Petersburg was a mere 710 square feet, smaller than the average one-bedroom apartment in Manhattan.
With the typical platform lying 187 feet below ground, St. Petersburg boasts the deepest subway system in the world. Admiralteyskaya is 282 feet deep.
With mosaics and murals, these hidden art courtyards showcasing street art, mosaics, and more give historic St. Petersburg, Russia some modern flair.