Most urban areas have undeveloped land that can be utilized productively. Follow these steps to create an oasis where people can meet, learn and develop new interests.
Choose an appropriate site. Several underutilized, contiguous city blocks near public transportation is desirable. Plant trees in places where their leaves will not block street lights too much at night.
Design the site with the help of architects, landscapers and zoo professionals. Have the feel of a rainforest, with ponds, streams, waterfalls, plants/animals and a research building.
Select your location with local factors in mind. The location will determine if it will be an open-air set-up or a greenhouse. Generally speaking, if you wanted a true rainforest setting in a place like NYC, you would need an enclosed greenhouse, owing to the winter temperatures. If that is not possible, a Northern American woodland theme would suit.
Apply to large chain stores for donations of labor and material in return for discreet, on-site acknowledgment plaques.
Approach investors or write a grant with your idea, design and cost.
Build and run site.