This is a Stereo- (or Anaglyph-) equi-panorama. 

You need red/cyan spectacles (red over left eye) to get the full impression.

Anaglyph:    http://en.wikipedia.org/wiki/Anaglyph_image

SMOLNY CATHEDRAL

Construction of the magnificent Smolny Cathedral was begun by Francesco Bartolomeo Rastrelli in the reign of Empress Elizaveta Petrovna and was completed by V.P. Stasov under Emperor Nicholas I.

The Cathedral is rightfully recognized as the gem of St Petersburg baroque. By the royal decree, it was named the Cathedral of all educational establishments.

It was in the period when the cathedral construction started that the Empress Elizaveta issued a decree reestablishing in the northern capital a five-domed structure – a characteristic feature of the Orthodox church.

The cathedral’s spectacular appearance, expressive design and external decor make it one of the highest achievements in world architecture.

http://eng.cathedral.ru/smolnii_sobor