Lake Khövsgöl is the largest lake in Mongolia by volume, an ancient rift lake 136 kilometres long in the far north near the Siberian border, holding seventy percent of the country's fresh water, so clear that a white disc can be seen eighteen metres down, and it is ridden around on horseback with reindeer herders in the taiga beyond its northern shore. Mongolians call it the Mother Sea. The lake is fed only by small mountain streams and carries almost no nutrients, so nothing clouds it, and from an open canoe launched from a quiet cove the pale stones and sunken logs seem to hang just below the hull; the shore is larch forest and meadow, with the Sayan mountains on the far side, and for a few summer weeks wildflowers cover the lakeside as the Darkhad and Tsaatan herders raise their gers and graze their horses. Along the shore stand ovoos, stone cairns strung with blue silk scarves, and passing herders add a stone and circle each one three times clockwise, as you do.
The way to see the lake is the way the country is crossed, on a hardy Mongolian horse along the wooded shoreline, sleeping in ger camps. North of the lake the taiga holds the Tsaatan, the reindeer people, perhaps two to three hundred of them in around thirty families, one of the last such cultures on Earth, living in bark-and-canvas tipis rather than the round felt gers of the plains and moving their herds through the forest; a ride of days reaches their camps, and a night with a family among the reindeer is the far end of the journey. In deep winter the whole lake freezes into a sheet of clear ice more than a metre thick, solid enough that Soviet convoys once drove fuel tankers straight across it from Siberia until the trucks that fell through were banned, and in early March the Ice Festival fills the surface with horse sledges, wrestling and ice sculpture. Khövsgöl is a sea that Mongolia keeps for itself, and the reindeer live at the end of it.