Having been in London numerous times, we decided to try the aquarium for a change. £20 each, no student discount, no 2 for 1 entry unless you have travelled national rail, etc. But it was good enough. Had it have been cheaper and there wasn't 475984570628745609 screaming school kids trampling all over your toes (although the kids seemed to really enjoy themselves), it could have been better. Interesting species but nothing that blew me away.