Looking for something to do on a wet and dreary day? Take your time wandering around the interesting displays at Museum of Ethnography. There's always an opportunity to learn something new.
You'll have no end of sightseeing choices in Budapest City Centre. Museum of Ethnography is a good place to kick off here, but there are numerous other fine places to consider. Buda Castle, Gellert Thermal Baths and Swimming Pool, and Parliament Building are close to the museum and will round out your day nicely.
