Garachico is one of the most idyllic and best-preserved towns on the islands, and it's well worth a quick visit. It was the main port of Tenerife until May 5, 1706, when Mt. Teide blew its top, sending twin rivers of lava downhill. One filled Garachico's harbor, and the other destroyed most of the town. Legend has it that the eruption was unleashed by an evil monk. One of the buildings that withstood the eruption was the Castillo San Miguel, a tiny 16th-century fortress on the waterfront. Island crafts, such as embroidery and basket making, are demonstrated inside. From the roof you can see the two rivers of lava, now solidified on the mountainside. You can also visit the Convento de San Francisco, which was unscathed, and the 18th-century parish church of Santa Ana.