Most accessible and potentially enlightening of the stops you can make along the north coast (and, indeed, the only one within striking distance of Dar), this once-prosperous slave and ivory trading port comes with a pleasant mix of beach and culture. Having served as the capital of German East Africa from 1886 till 1891, today much of the town has gone to seed, but there are glimmers of its former glories, if you can see past the decay and the tumble-down facades. It's also a popular weekend getaway for the Dar crowd, so there are an inordinate number of resorts, few of them worth recommending.
Although there had earlier been a more ancient community here, it was only in the late 18th century that Omani settlers set about extracting taxes from the locals and trading in salt farmed along the town's northerly shore. At the heart of present-day Bagamoyo is a crumbling, still-inhabited Swahili stone town (properly known as Dunda), which -- together with the chance to spot a few examples of German colonial architecture and a 19th-century prison-fort built by an Arab slaver -- merits some on-foot exploration. The town feels like a place that's permanently on the cusp of some sort of minor renaissance, and there are a number of centers where local artists work and sell their paintings and sculptures. You might want to pop into The African Modern Art Park (opposite the Old Post Office Hotel), where Saidi Mbungu (tel. 078/284-8547), himself a talented artist, can tell you about some of the work that's happening to teach children through art. Or perhaps visit the nearby Bagamoyo Talent Studio (a small room diagonally across the road from the Old Boma), where artists such as Emmanuel Philip Kuta (tel. 078/719-4323) and his partner, Lucas, will tell you about the struggle to be an artist in a poor country.
Besides exploring the old town and hanging around the dhow harbor -- a lively place to observe the fishermen in action and perhaps sample some of their catch, which they deep-fry and salt at the stalls on and around the beach -- Bagamoyo's biggest draw (aside from Kaole) is the Catholic Museum (tel. 023/244-0010 or -0063; Tsh1,500; daily 10am-5pm). The museum is actually a group of late-19th-century church buildings, including the Holy Ghost Church, where David Livingstone's body spent a night before being packed off to Zanzibar and onward to Westminster. The Holy Ghost Mission -- East Africa's first Christian mission -- was initially established as a shelter for children rescued from slavery. The museum itself provides plenty of insight into the scourge of slavery, but besides coming face to face with some of the tools of the trade and many disheartening images, you need to work quite hard to patch the discombobulated narrative together -- good enough reason to take on the services of the local guide (Tsh10,000 for a 1-hr. tour of the museum and the entire grounds).
To pick through another, much earlier layer of Bagamoyo's history, head 5km (3 miles) south along the coast to the crumbling Kaole Ruins (Tsh2,000; daily 8am-5pm). These are the remains of a medieval Shirazi settlement (presumed to have been built around 1250), which some believe may have been a kind of religious enclave, with a few poignant archaeological traces, including a well-preserved graveyard and a 15th-century mosque. Evocative as the overgrown site is, it's difficult to get a handle on the place without a guide, but be warned that whatever you're told will probably be highly speculative; the site is not yet fully understood by scholars trying to figure out exactly what happened here.