(CNN) — Vast as a sea and deep as an ocean trench, Russia's Lake Baikal is one of the world's great natural wonders.
With a surface area bigger than Belgium, it contains nearly one quarter of all the world's freshwater, which is more than the five American Great Lakes combined.
Baikal is truly a lake of superlatives.
The Earth's deepest inland body of water, its massive stone basin is so large that all of the rivers on the planet would take an entire year to fill it.
While more than 300 rivers flow in, only one -- the Angara -- flows out, eventually draining into the Arctic Ocean, hundreds of kilometers to the north.
Heart of Siberia
Despite threats from oil pipelines and other human activity, Lake Baikal remains largely pristine, its ecology insulated from environmental degradation by its sheer immensity and far-flung location.
Located in the heart of Siberia, it sits 3,500 kilometers west of the Pacific and over 4,000 kilometers east of Moscow.
The gateway to the lake is the Russian city of Irkutsk, a stop on the famed Trans-Siberian Railway, which many visitors (on relaxed schedules) use to arrive and depart.
There are also direct flights to Beijing and Moscow.
Regardless of season and location, the mesmerizing beauty of Baikal draws artists, photographers and intrepid tourists in equal measure.
With its unique flora and fauna and fascinating local culture, Siberia's sacred sea is well worth the journey.