Chivyrkuisky Isthmus

The Chivyrkuisky Isthmus is a broad land bridge that connects the island-like mountainous part of the Svyatoy Nos ("Holy Nose") peninsula to the eastern shore of Lake Baikal.

[3] The isthmus is almost divided in two by a shallow body of water, Lake Arangatuy (or Bol'shoy Sor), measuring about 13 by 7 km and about 54 km2 of area.

The lake is fed on the eastern side by streams from the mainland, and its outlet is near the north corner of the isthmus, near the "island", just east of the small village of Monakhovo - Zmeyevaya.

Many rare bird species nest on its shores: whooper swan, black-throated loon, Eurasian curlew, and others.

The waters may be up to 80 °C, and contain high levels of dissolved salts and other chemicals, up to 3 g/L – chiefly sodium sulfate, chloride, and fluoride, as well as silicic acid.