Lonar Crater Lake, India
This is the oldest crater lake and it’s caused by an asteroid impact approximately half a million years ago. Give or take a few ten thousand years, of course.
Okama Crater Lake, Japan
This one is also known as the Five Colour Pond, since it actually changes colour depending on the weather conditions. Ain’t science amazing?
Kelimutu Crater Lakes, Indonesia
There’s three lakes here, and they each have a distinct water color. It’s weird and I don’t exactly understand the science behind it, but it is a very beautiful thing to see.