As a species, we need multiple paths to survival. One of which is living in space. With this in mind, companies like SpaceX have plans to colonize Mars. But why Mars? It is the next most habitable planet after Earth. It contains water, temperatures that are not too hot nor too cold, enough sunlight, ability to adapt to its gravity, an atmosphere, and similar day/night rhythm’s to Earth.

Elon Musk wants to make a reality, starting by sending humans to Mars in 2024. Musk first plans by testing “planet hops” to refuel rockets in 2019. In 2020, SpaceX’s Starship testing will begin and eventually reach Mars in 2022 without humans. Assuming all goes well, Musk plans on sending humans to Mars in 2024 (with two unmanned cargo ships) the next time Earth and Mars are aligned. The very next year in 2025, Mars’s first human colony could appear, which would eventually expand into towns and eventually cities, offering habitats, greenhouses, life support, etc. By 2050, Musk is aiming for an entire city. By 2117, The United Arab Emirates wants to see a city of 600,000 people.
If this doesn’t scare you, I don’t know what will.