51km (32 miles) S of Tokyo
If you take only one day trip outside Tokyo, it should be to Kamakura, especially if you're unable to include the ancient capitals of Kyoto and Nara in your travels. (If you are going to Kyoto and Nara, I would probably choose Nikko.) Kamakura is a delightful hamlet with no fewer than 65 Buddhist temples and 19 Shinto shrines spread throughout the town and surrounding wooded hills. Most of these were built centuries ago, when a warrior named Minamoto Yoritomo seized political power and established his shogunate government in Kamakura back in 1192. Wanting to set up his seat of government as far away as possible from what he considered to be the corrupt Imperial court in Kyoto, Yoritomo selected Kamakura because it was easy to defend. The village is enclosed on three sides by wooded hills and on the fourth by the sea -- a setting that lends a dramatic background to its many temples and shrines.
Although Kamakura remained the military and political center of the nation for a century and a half, the Minamoto clan was in power for only a short time. After Yoritomo's death, both of his sons were assassinated, one after the other, after taking up military rule. Power then passed to the family of Yoritomo's widow, the Hojo family, who ruled until 1333, when the emperor in Kyoto sent troops to crush the shogunate government. Unable to stop the invaders, 800 soldiers retired to the Hojo family temple at Toshoji, where they disemboweled themselves in ritualistic suicide known as seppuku.
Today Kamakura is a thriving seaside resort (its pop. is 173,500), with old wooden homes, temples, shrines, and wooded hills -- a pleasant 1-day trip from Tokyo. (There's also a beach in Kamakura called Yuigahama Beach, but I find it unappealing; it's often strewn with litter and unbelievably crowded in summer. Skip it.)