The most awe-inspiring of Inca contributions to material culture was in architecture. Inca architecture had not the subtlety of the
Mayan, with its profuse ornamentation; nor had it the emotional impact of the Aztec; but Inca engineering and structural
daring--the grandiose concept of its cities and the handling of rock mass--finds no rival in either the New World or the Old.
The number and size of Inca structures, even in ruins, is simply overwhelming. Sites such as Machu Picchu, perched in a saddle
10,000 feet (3,000 meters) high between two Andean peaks, gives an idea of what Inca urban planning must have been.