The Horniman is the reason to come to Forest Hill, and it is one of London's most likeable museums. Frederick Horniman, a Victorian tea trader, filled it with the natural history specimens, musical instruments, and ethnographic objects he amassed from around the world, and the collection still has the cheerful, slightly overstuffed quality of one man's curiosity. Its mascot is a walrus stuffed by a taxidermist who had never seen a live one and so smoothed out all its wrinkles — comically, gloriously wrong.
Entry to the main galleries is free. There is a small aquarium, a hands-on natural history room, and a much-loved music gallery, while the surrounding gardens climb to a terrace with one of the best free views over central London. It is an easy Overground ride from the centre and makes a fine half-day with children or without.