The building appears almost surreal in its design, due to its dominant dome which resembles more a "cut-away" illustrative architectural drawing, a section, than a realised project. Inspired by the Pantheon in Rome the "dome" is unique, appearing as a half-dome or "semi-cupola." It is in reality an enormous niche — open to the elements — thus it seems that one views the interior from the exterior. A similar, but less theatrical, construction can be seen crowning the classical temple front of Alberti's Basilica of Sant'Andrea in Mantua, built in 1470.