Crystal Island: A giant glass tent
Gaining preliminary planning permission by Moscow city planners in 2008, this $4 billion tent was to be built in Moscow, standing 450m high and spanning 2.5 million square meters, 7.5 km from the Kremlin.
This “city-in-a-city” would be a home to 30,000 people and would contain shopping centers, theaters and a school. (This next part I had to quote, because it is just hilarious), “The exterior of said tent would be covered in solar paneling to both generate electricity for the enclosed community and blind the f****ing s**t out of anyone driving by.”
However, due to the financial crisis, these plans were postponed. The architect behind this plan, Baron Foster, built a smaller version of this sub-city in Kazakhstan in 2010 (below).