Karahunj, near the city of Sisian, is an astronomical observatory from some time prior to 2000BC. It consists of basalt stones, certain weighting several tons, 76 of which have apertures formed near the top. It is unclear though, how they were used and what was observed.
Khndzoresk is a cave village, where dwellings were hewn into the soft rock amidst weird looking limestone karst rock formations. They housed people till the 19th century.