The Cabildo of Buenos Aires is the former colonial government house on Plaza de Mayo. The white facade is smaller than the original building, after later avenue construction cut into it, but it remains one of the key surviving colonial landmarks in the city centre.
Inside, the museum gives useful context for the Viceroyalty of the Rio de la Plata and the political events that shaped early Argentine independence. The balcony also gives a good view back across Plaza de Mayo.