Lake Toba is a very big and deep lake located in Indonesia. It’s so big that you may not even be able to see the other side of the lake! This lake is very special because it was formed a very long time ago, around 75,000 years ago when there was a super huge volcanic eruption.
Imagine a big mountain called a volcano that had a lot of hot rocks and ash inside it. When it became too hot and started to shake, it exploded and threw all the hot rocks and ash high up in the sky. The explosion was so big it created a big hole where the mountain used to be, and that hole became where Lake Toba is today!
The lake is so big that it also formed an island called Samosir and created other smaller lakes around it. There are also many cool things inside the lake, like different kinds of fish and plants that you can't find anywhere else in the world.
Many people visit Lake Toba to hike and see the scenery or go swimming and boating in the cool water. It’s a really cool place to visit and it’s all thanks to the big volcanic eruption that happened a really long time ago.