Write a sentence about why it was such an achievement for someone to circumnavigate the globe

Because it proved to the world that the world is round.

After Christopher Columbus discovered the Americas, and was successful in changing the way European people thought about the Earth being a flat surface that could not be navigated without falling off the end of the horizon, many more voyages were planned in order to continue finding new trading routes and new lands.

Between 1519 and 1522 a Portuguese explorer known as Ferdinand Magellan set out to a new quest under the commission of the Spanish Crown to reach the East Indies this time. The adventure ended up being the first Earth circumnavigating enterprise ever attempted. Although Magellan did not complete the entire trip, some of those who set out with him, did.

The result was the discovery of lands that could be reached by navigating down the tip of South America (most of the South East Asian islands), and the possibility of reaching South East Asia and India, and the islands on the Pacific Ocean, going West, instead of East. This remarkable feat suddenly completely changed the concept that Europeans had about their planet, and it also changed the dynamics as the European powers, now aware of these possibilities and potentials, rushed to capitalize on them and establish their own routes and also colonies. The map of the world had completely changed for Europe.