Why can you see the borders between nations from above?

World War I historical overview available at https://www.youtube.com/watch?v=Em8Jn...
Why can you see the borders between nations from above?
Hello, buddies. While several of the surrounding nations have unidentified borders. And on occasion, when there is an issue, they exploit that as a pretext to act out. Other nations have borders that are fairly distinct. Even space-based satellites can observe it. Here, we'll look at which nations they are.
First, let's talk about the US-Mexico border. Early in the 20th century, Calexico and Mexicali, though situated in two separate nations, were referred to as twin cities. Calexico is a 40,000-person American city where the majority of the population is Spanish. Mexico's Mexicali, home to 1,120,000 people. These two cities look extremely different from space.
due to the US