MACAPÁ , on the north bank of the Amazon and right on the equator, is the gateway to the state of Amapá and home to three-quarters of its population. Surrounded by uninhabited forests and hills, it dominates the northern section of the Amazon estuary. If you're coming by ferry from Belém you'll actually arrive to the southwest at Porto do Santana , just twenty minutes by bus or an hour by boat from Macapá, though it lies on the other side of the equator. The airport is 4km from town on Rua Hildemar Maia (tel 096/223-2323). The Rodoviária faces the Polícia Técnica, 5km outside town on the BR-156; from there, local buses run to Praça Veiga Cabral in the centre. The countryside around Macapá is, like the Ilha do Marajó in the estuary, roamed by large herds of water buffalo. In town there is not a great deal to do. The highlight is the Fortaleza de São José (daily 8am-6pm), one of the largest colonial forts in Brazil, built in 1764 out of material brought over as ballast in Portuguese ships, in response to worries that the French had designs on the north bank of the Amazon. It is often closed, but nobody will mind if you slip through the enormous main gates for a stroll along the battlements. There's an interesting daily artisan market nearby on Canal da Fortaleza, and you could fill some more time checking out the eighteenth-century Igreja São José de Macapá on the Praça Veiga Cabral and the Museu Histórico at Av. Mário Cruz 17 (Tues-Sun 8am-noon & 2-6pm). There's also a small private museum, the Instituto de Estudos e Pesquisas de Plantas Medicinais (IEPA) at Av. Feliciano Coelho 1509, holding the Valdemiro Gomes collection of minerals, Amazon woods and medicinal plants (Mon-Fri 9am-noon).