Kaduna sits on the river that shares its name, a sprawling city that once served as the capital of Northern Nigeria under British rule and kept that role through the early years of independence. The colonial legacy is still visible in the wide boulevards and the old administrative buildings — particularly Lugard Hall, the former seat of the Northern Nigerian legislature, which still functions as the state assembly and is one of the most significant political buildings in the country.
The city is not a tourist destination in the conventional sense, but it has a particular energy. As one of the major crossroads of northern Nigeria, Kaduna is where the largely Muslim north meets the Christian south, and that mix gives the city a cultural complexity you do not find in more homogeneous places. Arewa House — the former residence of Sir Ahmadu Bello and now a museum of northern Nigerian history — is worth a visit if that history interests you. The Central Market is enormous and chaotic and one of the largest in the north.
Most travellers pass through Kaduna on the way to somewhere else, and that is a perfectly good use of the city. It is well connected by road in every direction and makes a natural stopover between Abuja to the south and Kano to the north. The nearby historic city of Zaria, with its ancient walls and the Palace of the Emir of Zazzau, is an easy day trip. And if you want the genuinely strange, Kajuru Castle in the hills to the southeast is a medieval German fortress that turned up in the Nigerian countryside in the 1980s — and is now a resort.