Set deep within the russian subcontinent , baikal is thedeepest , oldest and most voluminous of all lakes , a superstar of superlatives in hydrology , geology , ecology and history .
With 12248 square miles of surface area , baikal averages 2442 feet deep-its crescent moon-shaped figure a vast rift valley that first appeared about 25 million years ago through the divergence of the planet 's crust .
Today , a wilderness of forest , plains and semidesert surrounds baikal in the grand landscape of siberia , though development along the shores of the lake occurred last century with the building of several urban and resort communities .