I guess the original plans for the National Wildlife Conservation Park (now the Wild Place Project) falls under the category of cancelled exhibits.
In total, the park was due to have ten different sections that were each based upon an area where Bristol were doing conservation work:
British Habitats
I think this was primarily an indoor space, that was going to include areas for breeding rare native species. Harvest mice were definitely planned, and I seem to remember that adders were as well.
China Montane Forest
This section was planned to be home to four species of mammal - the takin, bharal, snow leopard and golden snub-nosed monkey. I think there were also plans for aviaries with pheasants and laughingthrushes.
Congo Tropical Forest
The original plans for this section were based upon the forests of the Eastern Democratic Republic of Congo, and were due to house bonobos, Hamlyn's guenons, black-and-white colobus, okapi, duiker and red river hog among the mammals. The plans also mentioned Hartlaub's duck, wattled crane, glossy ibis, hamerkop and black-billed turaco, gaboon or rhinoceros viper and hingeback tortoise, tree frogs, goliath and sun beetles, saturnid moths, African flower mantis, giant Congo millipede and a dozen species of freshwater fish.
This section is sort of happening, except there have been plenty of swapped species - gorillas instead of bonobos, mangabeys instead of guenons or colobus, slender-snouted crocodiles, grey parrots and cichlids, which were not included among the dozen planned fishes. Mandrills are due to come later, as are okapis - the only species from the original plans planned to move in here.
Costa Rica Swamp Forest
This was to be an indoor house with free-flying birds and butterflies and free-roaming lizards. The main attractions however were to be two enclosures with underwater viewing, one for manatees and the other for American crocodiles, mixed with a variety of Caribbean fish species. In the original-original plans, this was called Central American Swamp.
Georgia Wetlands
This was to be primarily a large walkthrough aviary home to a variety of birds including greater flamingos. There were also going to be separate enclosures for Eurasian otters and raccoon dogs.
In the earlier iteration of the plans, this was to be a British Wetlands display, with otters as in the later plans but also an enclosure for water voles. Inhabitants of the aviary were to include egrets, avocets, oystercatchers, turnstones, lapwings and corncrakes among other birds.
Indian Ocean Coral Reef
This was to be a two-part indoor display contained within a large dome, one based on the forests of the Comoro Islands and home to Livingstone's fruit bats, mongoose lemurs, Comoro flap-nosed chameleon and Comoro day gecko, with the other part being a tropical reef aquarium again based on the Comoro Islands. The plans mention twenty-three fish species, including blacktip reef sharks and, perhaps the most out-there species in the plans, roughskin spurdogs. Four species of invertebrate were also included here, including live corals.
Nepal Grasslands
A large series of outdoor paddocks that were due to be home to Bengal tiger, sloth bear, dhole, Indian rhinoceros, grey langur, banteng, barasingha, axis deer and hog deer.
Sumatra Rain Forest
This section was planning to house Sumatran tigers, lar gibbon, Sumatran orangutan, Malayan tapir and Asian small-clawed otter among the mammals. There were also due to be blood pythons, red-tailed ratsnakes, spiny turtles, Sumatran gliding tree frogs, seven named bird species and five named species each of freshwater fish and invertebrate.
Tanzania Savannah
The original plans for this section included a giant paddock with a safari jeep ride through it, that would have housed giraffe, greater kudu, zebra, wildebeest and ostrich. There would also have been separate enclosures for warthog, black rhinoceros, cheetah, African wild dog, dik-dik, banded mongoose, zebu cattle and vulturine guineafowl. The plans also included a Ranger Station that would have housed leopard tortoise, white-throated monitor, African bullfrog, dung beetle, train millipede, praying mantis, termite, acacia ant and cichlids.
There were other plans available that preceded this one, which also mentioned blesbok, secretary bird, wattled crane and francolins in the drive-through section.
This section is also sort-of happening, but is now based on Central Africa instead. It already has giraffe, zebra and cheetah, with ostrich due to move over soon and black rhino planned for the future.
The only part of this plan which has happened, pretty much unchanged from the original plans, was British Ancient Woodland that was renamed as Bear Wood.