We liked smithsonian museums (history + air & space?) in DC. We also saw couple of others close by and generally liked them all. If I recall, guide was free and she was knowledgeable and enthusiastic.
Queensland Museum Kurilpa in Brisbane. Spent a whole day in there and wasn't bored for one second.
Battle of Blood River - very interesting to visit the East & West complexes by walking across the bridge (twice if you can - the contrast in the stories is well worth the amble back and forth)
The Science Museum in London - I went there in January 1994 when I was in the UK for 2 weeks on holiday... well worth it - spent most of the day there taking 35mm photos (this was pre-digital photography).
Cars on Display (Top to Bottom)
Fiat 600 (top) Citroën 2CV
Morris Minor MM
Volkswagen Type 1 (Beetle) Saab 93
NSU Prinz (bottom)
The passing of time is made visible at Matjiesfontein's museums. The incomparable collections will take you back 120 years into the past and show you just what life was like at this colonial outpost.
cape town:
take a walk thru the company gardens - dont follow the main pathway (black), take the one alongside (green) - there are all sorts of interesting things peppered along the way.
buy a bag of peanuts at the entrance to the pathway and hand feed the squirrels (not the ramaphosa one) as you walk thru.
have lunch at the company gardens restaurant
In the heart of the Mother city, within the richly historical Company's Garden, lies a restaurant built for children, families and visitors alike. Inspired by nature and by tales rooted in the past, this gentle space offers a point of peace within a buzzing urban metropolis.
www.thecompanysgarden.com
then explore these - all close together:
0) parliament buildings (no access - just as a reference point)
1) national art gallery
2) jewish museum (id document required) - saturdays closed
3) holocaust centre (id document required) - saturdays closed
4) sa national museum
5) planetarium