During the housing boom in 2006, 49,000 condo units were built in Miami. As the crash came, building came to a screeching halt and buildings became bank-owned one by one.

Seven years later, there are just 2,400 unsold units left, barely a year's worth at the current sales pace. Prices have appreciated nearly 25% from a year ago, according to the Miami Area Association of Realtors.

Now, cranes are back to swinging above the city from every angle, just as they did during the housing bubble in 2006.