The shrines and temples of Nikko have been recognized by UNESCO as a World Heritage Site. Here, you can visit the Toshogu Shrine, which dates from the 17th century and is a monument to (and the mausoleum of) Tokugawa Ieyasu, the founder of a shogunate that ruled Japan for 250 years. Travelers day-tripping from Tokyo generally focus on the sacred sites, but if you have extra time, explore the area’s beautiful waterfalls and lakes.