Rhinos at the Singapore Zoo (2004)©
When I travel I like to visit museums, zoos, aquariums and gardens. The web allows you to go back and read about some of those exhibits you had to rush past. Some of the more notable ones I have visited and would recommend include:
the Metropolitan Museum of Art (New York) - this is awesome
the Guggenheim (New York)
the National Gallery of Art (Washington DC)
the Museum of New Mexico (Santa Fe)
the National Gallery (London)
the Tate Gallery (London and Liverpool)
the British Museum
the Museum of London - relocating
the Louvre (Paris)
the Musée d'Orsay (Paris)
Art Gallery of New South Wales (Sydney)
the Museum of New Zealand (Wellington)
the Canterbury Museum (Christchurch) - closed for redevelopment
the Otago Settlers Museum (Dunedin)
the Prado Museum (Madrid)
the Museo Thyssen-Bornemisza (Madrid)
the Albertina Museum (Vienna)
the Royal Museums of Fine Arts (Brussels)
the Glenbow Museum (Calgary)
the Manitoba Museum NEW (Winnipeg)
the National Palace Museum (Taipei)
National Gallery of Victoria (Melbourne)
Google Arts & Culture also has great coverage of these museums and more.
Artnet has a comprehensive database of artists and their works.
Art UK NEW has a large online collection.
Natural History Museum and Science Museum (both in South Kensington, London)
American Museum of Natural History (New York)
Naturhistorisches Museum (Vienna)
National Maritime Museum (Greenwich, England)
National Motor Museum (Beaulieu, England)
National Railway Museum (York, England)
La cite de Sciences et de l'Industrie ( Paris) - well worth a look
Deutsches Museum (Munich and Schleissheim, Germany)
National Air and Space Museum (Washington DC) - I have been three times
Museum of Flight (Seattle)
Museum of Science and Industry (Chicago)
Royal Aviation Museum of Western Canada (Winnipeg)
Powerhouse Museum (Sydney)
Museum of Transport & Technology (Auckland)
Otago Museum (Dunedin)
the Royal Botanic Gardens at Kew (London)
San Diego Zoo (Southern California)
the National Zoo (Washington DC) - don't miss the "Orang utan Transportation System"
Longleat (England)
Ueno Zoo (Tokyo)
Mandai Bird Paradise (Singapore) - was the Jurong Bird Park
Wildlife Habitat (Port Douglas, Australia)
Orana Wildlife Park (Christchurch)
Monterey Bay Aquarium (a day trip from San Francisco) - the sea otters are wonderful
the Imperial War Museum (London and Duxford)
the RAF Museum (Hendon, London and Cosford)
the National Army Museum (Chelsea, London)
the Tank Museum (Bovington, Dorset)
the Royal Navy Museum (Portsmouth)
the Fleet Air Arm Museum (Yeovilton, England)
the Musée de l'Armée (Paris, France)
the Royal Army and Military History Museum (Brussels, Belgium)
the Australian War Memorial (Canberra)
Air Force Museum (Wigram, Christchurch) - RNZAF
National Army Museum (Waiouru, New Zealand)
Torpedo Bay Navy Museum (Devonport, Auckland) - RNZN