A proposal for a mile-high tower in Times Square. Courtesy eVolo The winners of this year's eVolo Skyscraper Competition deal with some daunting themes, including overcrowding, global warming, and environmental disaster.

The contest, sponsored by eVolo Magazine and now in its 10th year, asks architects to envision the future of vertical living.

Nearly 500 contestants submitted their ideas for the skyscrapers of tomorrow, and three winners and 20 honorable mentions were selected by a jury of leaders in the fields of architecture and design.

These buildings may not be feasible today, but they attempt to answer some big questions about the future of urban spaces.