Tanzania's National Museum.

I somehow managed to get inside. You can't buy a ticket with cash—only card or local mobile transfers. Of course, card payment doesn't work (no connection to the bank) :) I had to buy a ticket using a mobile transfer with help from locals.

The museum is amusing: a few exhibits on historical topics, a hall with paintings and photos of local presidents, and that's it. Except the main halls are all mixed in with some kind of technical rooms. You walk around and can't tell if you're done or if there's more.