Bangladesh

Flat and flood-prone, Bangladesh is sandwiched between India and Myanmar. Its defining feature is a massive delta, which is created by the Ganges River as it spills out into the Bay of Bengal. Most of the country sits an an altitude of less than 50 feet above sea level. 

One thing you can't see from satellite pictures is Bangladesh's impressive population density. The country is home to nearly 160 million people, all of whom live in an area that is roughly the size of Iowa. If you throw out tiny territories like Macau, Monaco, and Singapore, this is the most densely populated country on earth by a wide margin.