Porto Novo is the capital city and one of the most interesting towns in Benin. It has a number of buildings dating from the period when the Portuguese used it as a base for buying slaves which were shipped off to the New World.
Other sights in town include the Musee Ethnographique which retraces the history of Porto Novo and has a good collection of Yoruba masks, the Palais Royal of King Toffa now a museum which gives you a good impression of how African royalty lived before Colonial times.
Just outside of town is the Grand Marche d’Adjara which is held every fourth day. There is also an interesting Brazilian-style church here which is now in use as a mosque. Another good option for a day trip is to hire a priogue and to make a trip to one of the villages on the lagoon.