Lake Toba - No. 2 Deepest Lake in Indonesia

FYI guys, the depth of Lake Toba reaches 529 meters, lohhh, losing to the deepest lake in Indonesia, namely Lake Matano which is in (Central Sulawesi) which is 590 meters!
and also the depth of Lake Toba is actually like the sea, yes, the underwater current is also heavy even though the top looks calm. Behind its depths there must be someone who asks about the kingdom under Lake Toba, WHAT IS THE MYSTERY OF LAKE TOBA?