The church of San Martino in Piazza Brembana and Lenna, it's the baptismal church of all the Upper Valley. It dominates, from the hill of the same name, the centres of Piazza Brembana and Lenna. The ancient church was rebuilt in neogothic style in the middle of 1800 by the Arch. Preda of Ponte S. Pietro's project. It keeps many important pictorial works, like the polittico of S. Martino, realized in 1503 by Lattanzio of Rimini; a big canvas by Gregorio Lazzarini; many canvases by Carlo Ceresa; works of carving, sculpture by Andrea Fantoni and some very valuable masterpieces from the local school.
The Bell Tower was designed by Mauro Cadussi, a great architect who was born in Lenna.