I've been to all corners of the world and I can totally agree with the others on this topic. Dakar is the pits of the world
Even compared to other West African ports I have been to like Accra, Abidjan, Cotonou, it is the only one I truely feared for my safety. There are some nice tours such as The Pink Lake, or The Ganvie Slave Island, but just getting off the gangway is a nightmare. Tenerife may be 'just another port', but at least you'll live through it!!!