The Armando Calcaterra Paleontological Museum is a small museum near Real de San Carlos with fossils and archaeological finds from the Colonia area. Its displays include remains of extinct South American animals such as glyptodonts.
It is a useful add-on if you are already visiting the Plaza de Toros or cycling north from Colonia's historic centre. The museum is modest, but it adds natural-history context to a part of town most visitors see only for the bullring.