Close your eyes and imagine living life under a dome while you stroll through Central Park with perfect weather and no pollution, or imagine floating 30 miles above Venus' surface in a blimp city covered in clouds. Better yet, submerge yourself in a city akin to Atlantis where you can run inside a crystal-clear globe that faces the deep sea and its residing marine life.  All these scenarios may seem surreal and impossible, but concept designs of such places have already been proposed, backed up and some were even set into motion. A number have failed, while others are still being developed.  Here are five concepts that have been proposed in the past that seemed too good to be true:  Ocean Spiral — Atlantis may be a myth, but a Japanese firm called Shimizu Corporation is trying to develop the next best thing to the lost city. Ocean Spiral would be the world's first underwater city. Shimizu said the $26 billion project would house 5,000 residents in a 500-meter deep crystal sphere city. The city would be entirely sustainable with its own fisheries, fresh water and energy reserves. Shimizu recently proposed the idea and is trying to find ways to gather money and build the concrete sphere under the sea.  HAVOC — Humanity still hasn't gone to Mars, but NASA is already planning to live in Venus. NASA's High Altitude Operational Concept presents the idea of sending two astronauts in a month-long mission to Venus. The astronauts would navigate around Venus' atmosphere in a blimp while they research expanding humanity's future is space. NASA said that eventually a stationary base with a permanent human presence could stay up floating around Venus' cloud city. Venus is not the first planet that presents the idea of human settlement in space. Other proposals for life on Mars and the Moon have also been presented in the past.  TRY 2004 Pyramid City — Shimizu is not a first timer at proposing wild concepts of cities. In 2010 Shimizu proposed building a pyramid city that would house 100-foot skyscrapers and a population of up to a million people. Unlike the underwater city of Ocean Spiral, TRY 2004 didn't seem as viable and didn't receive much support. Designers at Shimizu wanted the skyscrapers to be suspended from giant tubes within the pyramid. They also wanted the tubes to contain power and utility supplies. On top of all that, the tubes would also have a transportation system that would help residents get to their offices, schools and homes.  World Islands — A lot of people dream of traveling the world and conquering it—in a philosophical way. Nakheel Properties in Dubai found a way for wealthy people to do just that. Nakheel created a visionary project named The World, which is a collection of 300 private islands that are shaped into continents. If you were to see the islands from a few miles up in the sky you'd see a map of the world. The islands are located off the shore of Jumeirah. The project was killed in 2003, but several celebrities and private investors bought some islands to show support. Years later, Nakheel may be able to finish construction of the islands and sell them between $7 million and $1.8 billion.  Manhattan Dome — You might've thought that idea of living under a dome only existed in a CBS drama, but in 1960 it was actually proposed to set up a giant dome over Manhattan. Engineer Buckminster Fuller and architect Shoji Sadao proposed the idea of installing a giant dome over Manhattan that would reduce pollution and regulate weather. The dome was expected to cover all areas between the East River and the Hudson River. Fuller believed the dome would reduce heating and cooling costs during the different seasons and that the cost of snow removal would pay for the dome in 10 years. Plans to construct the dome were never set in motion because it was simply ahead of its time.
Here are five concept designs of future cities that resemble a sci-fi movie setting but have actually been proposed.