The Palazzo Contarini del Bovolo is a small palazzo in Venice, Italy, best known for its external multi-arch spiral staircase known as the Scala Contarini del Bovolo .The palazzo is located in a small, less-travelled calle near Campo Manin, about half-way between Campo San Bartolo, at the foot of the Rialto, and Campo Santo Stefano. The staircase leads to an arcade, providing an impressive view of the city roof-tops. This palazzo has been visitable since February 2016.

More details: https://en.wikipedia.org/wiki/Palazzo_Contarini_del_Bovolo