The church -- more formally known as the Cathedral of St. Basil the Blessed -- erupts in a riot of color and patterns from the south end of Red Square. Built on the orders of Ivan the Terrible to commemorate the capture of Kazan and Astrakhan, it was formally consecrated on June 12, 1561.
The church's nine onion domes -- meant to honor the spirit of the church's inspiration, St. Basil, a religious eccentric who breezed through Russian winters in the nude and was one of the few men able to speak his mind to the tsar -- took on their vivid colors only gradually, as Russian fashions and technologies changed. (As many architectural legends seem to go, Ivan IV is rumored to have blinded the cathedral's designer to prevent him from repeating his magic.)
The church, which narrowly escaped destruction by the secular Bolsheviks, is considered structurally and aesthetically unique, with no obvious antecedent or successor in Russian architecture. Together with the Kremlin and Red Square, it was named as a UNESCO World Heritage Site in 1990.
On the occasion of its anniversary, it's been granted a $14 million restoration and -- the ultimate honor -- a commemorative doodle by the Google search engine. Russia's RIA Novosti has also produced a panoramic virtual tour of Russia's most famous church.
-- Daisy Sindelar