By Rebecca Morelle
Science reporter, BBC News, Costa Rica
The glass frog is one of many species found at the research centre
Trekking through the dense forestation of the Costa Rican Amphibian Research Center is like stepping back in time.
More than 50 species of amphibians of just about every variety of shape, size and colour that you can imagine thrive within the 112 acres (45 hectares) of pristine rainforest.
Brian Kubicki, who set up the centre in 2002, says: "In a lot of other highland areas, species have really declined."
The herpetologist has spent years turning his patch of land into an amphibian haven - and the site now has the highest concentration of amphibians anywhere in Costa Rica.
A team from Manchester University and Chester Zoo, who are being followed by the BBC, visited the rainforest during daylight and after nightfall.
Here are some of the incredible amphibians that live in this mist-shrouded forest.
THE POISONOUS FROGS
Andrew Gray from Manchester Museum handles some of the poison frogs
Poison dart frogs are one of the few amphibian species that come out during the day.
As their name suggests, these little frogs are highly toxic - and any predators who are not put off by their bright warning colours will either become extremely sick or die.
The poison even has a strong effect on humans - if it gets into an eye, it can cause temporary blindness. One species found in Colombia has enough poison in its skin to kill 10 people.
THE GLASS FROG
Brian Kubicki explains how glass frogs got their name
One of the Brian Kubicki's key species is the glass frog - a beautiful specimen that is found by streams in rainforests.
His research has focussed on the ecology, biology and taxonomy of these creatures.
He has been working on modifying and conserving the habitat around his research centre to make it an area where the frogs are able to thrive.
THE SPLENDID LEAF FROG
Andrew Gray finds a rare splendid leaf frog
These frogs are extremely rare.
They live high up in tree tops, and only breed in pools that have formed in the logs of fallen trees.
At the Costa Rican Amphibian Research Center, Brian has created special tubs that mimic water-holding logs where the frogs can lay their eggs.
THE SCREAMING FROG
The high-pitched scream of the smoky jungle frog
Smoky jungle frogs are huge, and can be found lurking around the ponds at the research centre.
They feed on a number of different animals, including small mammals and even other frogs.
If anything disturbs them, they let out a high-pitched scream to scare off potential predators.
THE LEMUR FROG
This is the lemur's last stronghold
The research centre is now the last stronghold for the critically endangered lemur leaf frog.
Several years ago, it was relocated here from its last known breeding site just before its habitat was destroyed.
Scientists on this conservation expedition are now investigating the genetics of this tiny frog to find out more about the species.
THE PIN-UP FROG
A jumpy encounter with the red-eyed leaf frog
The spectacular colouring of the red-eyed leaf frog has made it the poster-child of the frog world.
Unlike many other species, populations are doing well, and it is the most widespread frog in Central America.