Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
These Landsat images show the remarkable transformation of desert sand in 1986 into green, circular fields—some as large as 1 kilometer across—by 2016
Public Domain.
