Castles
You can't miss a visit to Thun Castle (see picture), one of the most beautiful and well preserved castles of the valley. You can reach it by foor or by bus departing from the village of Ton.
Valer Castle, recently opened to the public.
https://www.visitcastelvaler.it
Nanno Castle, suspected to be haunted by the lost souls of two lovers condemned to be walled in because their families did not approve of their love.
http://www.visitvaldinon.it/it/da-vedere/arte-e-cultura/castel-nanno/
Art and culture
The Rhaetian Museum in Sanzeno
https://www.cultura.trentino.it/Luoghi/Tutti-i-luoghi-della-cultura/Musei-e-collezioni/Museo-Retico
St. Romedio's sanctuary (see picture) can be reached via a nice walk in the woods from Smarano or an impressive path carved into the rocks from Sanzeno. The sanctuary's large wood is home to Bruno, a brown bear illegaly kept in a very small cage. No more fit to be freed, the bear, traditionally linked to St. Romedio, has been rescued and entrusted to the sanctuary and represents now a friendly and nice sighting for children and adults.
https://www.santuariosanromedio.it/