http://www.slate.com/articles/news_and_politics/metropolis/2015/05/the_land_tax_what_happened_to_towns_like_fairhope_alabama_that_tried_georgism.html

In 1879 the American political economist Henry George proposed a policy to address economic inequality: Tax land—not what’s built on top of it. Tax a parking lot, a seven-story building, and a skyscraper based solely on the value of their footprints. Tax landowners that way, George reasoned in Progress and Poverty, and they couldn’t afford not to develop their holdings. The “single tax” on land would create a strong incentive for bigger buildings, more offices, and more apartments, lowering costs for businesses, shops, and residential tenants. It would remedy the regressive advantage of the urban landowner, to whom George wrote: “[W]ithout doing one stroke of work, without adding one iota of wealth to the community, in ten years you will be rich!"