Photo: Mx. Granger, CC0 via Wikimedia Commons
A Portuguese 18th-century building: an example of a furnished home from those times.
© OpenStreetMap contributors
Museo Municipal Dr. Bautista Rebuffo
Museum in two floors presenting objects of daily life 200 years ago as well as the works of scientists and explorers that have lived and worked in the town. In the room dedicated to a biologist there are various two-, six-, and eight-legged creatures on display, as well as small and very large fossils. If you're lucky you get to meet the offspring hanging next to the fusebox in the back corner. This museum is also where you buy the U$50 ticket that allows you into all eight museums.
Small brick ruin between the lighthouse and the main square. You would not know what kind of building it was if there weren't a sign next to it.
Museo Naval
Casa del Virrey
Reconstructed somewhat on the ruins of the original building. Don't miss the whale skeleton on display just to the west of it!
For a nominal fee you can go up to the top of the lighthouse (faro) and see most of the city and look out over the city and Rio de la Plata. On a clear day probably even Buenos Aires is visible. The lighthouse was built in 1857 and it is 26.92 m high with 118 steps. Its light is not white but red.
Archivo Histórico Regional
The house was built by the Portuguese in the 18th century and called "Casa de Palacios". The museum shows documents from the various epochs in Colonia's history.