When a city as densely populated as New York City has no room left to build much needed public green spaces, what do you do? Build them above and under the city, of course.

Inspired by the High Line project, a green refuge installed on an unused, elevated rail line in New York’s lower west side of Manhattan, the Delancey Underground project is to convert an abandoned trolley terminal below Delancey Street into a green tech-powered subterranean park.

The terminal space is 60,000 square feet (1.5 acres or 5,575 square meters) in size with steel columns supporting 20-feet high vaulted ceilings, and has been in disused since 1948.

Contrastingly nicknamed the “LowLine”, the project is a collaborative venture by architect James Ramsey, PopTech executive Dan Barash and money manager R. Boykin Curry IV. The park will incorporate fibre optics to catch sunlight and transmit it underground, generating enough sunlight to support photosynthesis. The use of solar technology will save on electricity and keep carbon emissions to a minimum.

In order to convince the Metropolitan Transit Authority (MTA) of the idea, the Delancey Underground team needs to build a “mini-LowLine” to prove the project’s feasibility.

If this project gets the go-ahead, and reaps similar successes as the High Line, it will set in motion a whole new thinking for urban spaces. Delancey Underground said in a statement: “The ‘LowLine’ is essentially part of the next phase in urban design, in which human scale and increasing resource scarcity force us to imagine smarter, more creative use of public spaces.”