What are zoos for? Their main function for us, visitors, consists in providing a close contact with animals and a possibility of exciting observation. As compared with first zoos, today's cope with this task much better – animals' housing conditions are close to natural. Visitors can observe the habits of animals as close as safety rules allow (the safety of animals is also taken into account). But so far no one has considered the possibility of admitting visitors inside cages or outdoor enclosures.

In a children's zoo in New York, one can observe the life of amusing tenants of American prairies – prairie dogs – being inside an outdoor enclosure. How is it possible? Not animals are separated off people, but people are separated off animals. Small glass cupolas are erected in the middle of a lawn. Their height allows nose-to-nose contact with prairie dogs. One can get to a cupola via a system of tunnels.
Here the inventive principle “The other way around” is employed.
A similar system functions in some aquariums – a transparent tunnel passes under the water and visitors can see submarine inhabitants in their proper surroundings.

 
Information source: The magazines “V Mire Zhivotnykh”, № 7-8, 2000. “Technics for young people”, №6, 2000.