Many of us remember watching the catastrophic events of the 2004 Indian Ocean tsunami and the 2011 Japan earthquake unfold. The loss of human life caused by these events remains up there with some of the most devastating natural disasters in recent times. The tsunamis created waves that reached 30 meters (100 feet) and 40 meters (130 feet), respectively. But tsunamis can be (and have been) a lot bigger than these.

This brilliantly put together video by RealLifeLore lays out the different types of tsunami, the science of what causes them, and asks how big these seismic sea waves can become.

Tsunamis are caused by large volumes of water being suddenly displaced, generally by an earthquake, tectonic activity, volcanic eruptions, or other underwater explosions. This was the case in the two recent tsunamis in Asia.

Then, there’s what is known as a megatsunami. These are capable of being notably larger and are generally caused by displacement of water caused by the impact of a material, such as an asteroid or landslide, into a body of water.

The most notable example of this was the 1958 Lituya Bay megatsunami in Alaska. A landslide caused by an earthquake crashed into the bay, causing a wave approximately 525 meters (1,722 feet) high. That’s considerably taller than the Empire State Building. 

However, this is still not the most deadly megatsunami in the past 100 years, nor is it the tallest one the world has witnessed. Check out the video below for more.