Countries trade resources to get what they need. One may have the land to grow a lot of crops while another has forests and can provide timber. While exchanges are not so cut and dry, this is the basic premise. However, sometimes things are just that simple.
Singapore, one of the smallest countries in the world, has a lot of money but not a lot of territory, particularly coastlines. Cambodia on the other hand has plenty of land but is poor. These circumstances lead the two countries to reach an odd agreement.
Billions of cubic feet of sand has been dredged up from Cambodia’s coastline and shipped by barge to Singapore. There, it has been turned into new cubic miles of Singapore territory. This land is now home to hotels and casinos among other structures. In return, Singapore has paid Cambodia well for this new land.