The quaint cobbled section of Calle Obispo between Calles Oficios and Mercaderes is lined with the oldest buildings in Havana. The row of 17th-century townhouse mansions includes the tiny La Casa del Agua La Tinaja, which can be easily overlooked given its small size. The shop offerss to pedestrians water that is filtered in large earthenware jars called tinajas and originally supplied by the two aqueducts built in Havana. There is no fixed fee for the water and is totally voluntary.
Stop by for a glass of water, but note that there may only be one glass: neck it without the glass touching your lips, like locals do. The cheery staff there also sell bottles of water to take away.