An overpowering blast of humidity hits visitors as they enter a jungle filled with ferns and rubber plants, clustered around what appears to be the primordial soup.
It feels like a tropical rainforest at the dawn of creation, but it is in fact a giant greenhouse near the centre of Switzerland's busiest metropolis - Zurich.
This is a small-scale model of the Masoala Rainforest in Madagascar, home to one of the richest biodiversities in the world.
The construction - forming part of the Zurich Zoo complex - houses hundreds of species of mammals, fish and insects indigenous to Madagascar.
Visitors to the simulation rainforest have the chance to see highly endangered animals roaming freely across an 11,000 square metre space, lofty enough to accommodate 20 metre high jungle trees.
The idea was the brainchild of zoo director, Alex Rübel, a veterinary surgeon by profession. He wanted to increase the conservation work of the zoo, and set up the rainforest project in collaboration with the Masoala National Park.
In total 17,000 plants indigenous to Madagascar have been imported to Switzerland.
Some of the tallest trees from Malaysia and Florida had to be pared down, to fit them into the 12-metre-long shipping containers.
There are also 2, 500 plants from nurseries in the Masoala National Park, which was set up by the zoo in collaboration with the development group, Care International.
The pink-flowered periwinkle spreads luxuriously over a stone bank, still glistening from the morning shower provided by rain collectors in the roof.
This is one of the plants plundered by the West for use in medical science – it’s an effective treatment for child leukaemia.
There are trees with strangely twisted roots, rubber plants sprouting giant bell-shaped flowers, and violent-green palms and ferns of all shapes and sizes. A rope bridge leads the adventurous visitor through the tangled jungle across a swamp, which some day soon will teem with life.
Born to be wild
Hundreds of different types of lemurs, birds, fruit bats, chameleons, iguanas, frogs and insects – all of them native to Madagascar – live in the "rainforest". Most of them are from European zoos.
They are able to forage for their own food among the fruit trees and jungle plants, with additional fodder being supplied by the zookeepers.
Visitors must stick to the path through the forest and keep their distance from the animals.
Dr Rübel told swissinfo: “The idea is to experience the animals as they are in the wild, so visitors will have to look carefully to spot them. We don’t allow anyone to feed or touch the animals.”
Preserving the rainforest
Madagascar is a conservation priority, with its unparalleled combination of diversity and its unique flora and fauna. Less than 15 per cent of the original native forest remains, most of it having been cleared by people or transformed by cattle and fire.
"Most of the animals living in Masoala are endangered because the rainforest gets cut so fast," Dr Rübel explained.
The fate of the forest is written in population growth and poverty, above all. The zoo director wants to make the public aware of the problems created by human exploitation of this unique habitat.
He hopes visitors to the project will give generously, providing the funds needed to help conserve Madagascar's tropical forests, while making economic development more sustainable.
swissinfo, Julie Hunt
The "Rainforest" covers a space of 11,000 square metres, next to Zürich Zoo.
The project costs SFr50 million and is funded from private donations and legacies.
Hundreds of animals, fish and invertebrates are being introduced to the simulation rainforest, starting in May.
Most of the trees are from plant nurseries in Madagascar.
The biggest trees imported for the project weigh nine tons and are 12 metres long.