The Portuguese Museum fills an 18th-century house in Colonia's old quarter with objects from the period when the town belonged to the Portuguese empire. The collection is small, but it helps explain why Colonia feels different from many Spanish colonial towns across the river.
Look for the old coat of arms that once stood on the city gate. It is the kind of modest museum that works best as part of a slow circuit through the historic centre, rather than as a stand-alone stop.