Are there really buildings under the water in the canals in Venice, Italy?

Question

Are there really buildings under the water in the canals in Venice, Italy?

Answer 1

if you mean utterly submerged by the water, I'd say no; but since it's pretty unlikely a building to float, then the basements actually are under the surface.

Answer 2

If you mean totally under the water the answer is NO; none of them is completely submerged by the lagoon.

If on the contrary  you mean partly immersed  the answer is YES since mostly of the buildings in Venice have their foundations  made direct in the water.