The only historic structure on the island worth mentioning (and some disagree its worth a mention) is the Kastro or small Venetian block house which is in some disrepair. It uses the walls of its interior houses as part of the exterior fortifications.
The block house is semi-difficult to find not withstanding Andi-paros only has two main streets. The main shopping street (below right) and the thoroughfare lining the harbor.
The attractions of Andi-paros are its several nice beaches where nudity is tolerated (and sometimes overdone as when small local children and matrons are present) and its laid back atmosphere.
Its very close to Paros with its airport and which is also well visited by ferry boats. This island is popular with Greeks, Italians and actor Tom Hanks even owns property here. Best off season!