Dries Buytaert

A large concrete dam spanning a deep canyon.
When the Hoover Dam was built, they used an enormous amount of concrete. If they had poured it all at once, it would have taken over a century to cool and harden. Instead, they poured it in blocks and used cooling pipes to manage the heat. Even today, the concrete is still hardening through a process called hydration, so the dam keeps getting stronger over time.