We had planned to see Natural History, and to look inside the Oratory - the Roman Catholic Cathedral for London. Natural History is an absolutely glorious building: sandstone and blue colour stone, terracotta tiling and ornamentation inside, over an iron frame. Huge, too. The Diplodocus replica skeleton inside is 100 years old, and the dinosaurs display is fairly much compulsory to kids of all ages. So around we go, and love it. The Earth Science wing also gets a look in: very good earthquake and volcano displays. Very interactive and geared for school visits, but one of the better ones we have seen - plenty for adults as well.
Brompton Oratory is plain on the outside, but Spanish-style ornate on the inside. We walk in on the tail-end of a mid-day Mass, which has a good following of the faithful. The Piccadilly Tube underneath echoes through the interior somewhat, which does rather reduce the ambience.