Baikal – the most ancient, deepest lake on Earth. And the most perplexing. Scientists continue to attempt to resolve its mysteries to this day. One of them, is how it was formed. The leading theory is that it’s the result of a rift – the lake formed as the result of a deep fissure in the Earth’s crust. Is that the case? And is it true that Baikal may one day become an ocean? Answers in this RTG TV film.