In pictures: Crossing the world's deepest lake

Lake Baikal, the world's deepest, offers astounding views along its shoreline - and winter tours of its frozen expanse have become increasingly popular.

With some trepidation, Oleg Boldyrev walked, and even rode, across the multi-coloured ice.

The giant lake creates its own climate - and winter around Baikal normally starts later than elsewhere in eastern Siberia. In late December, the lake finally freezes over - but there is very little snow until mid-January.

Olkhon, the largest island in the lake, is a popular tourist destination, when Covid restrictions allow.

Soon, the ice is thick enough to walk on - and even for some lighter cars to drive. In February, the ice road from the mainland to Olkhon Island opens for a short period, depending on the thickness.

Images of the ice have drawn lots of interest on social networks.

A bike with studded tyres is one of the ways to explore this frozen expanse.

Skating is also popular.

The lake offers many miles of perfectly smooth ice. First-time visitors may be taken aback by the massive booms and cracks as it expands and contracts, in the daytime. This is normal, locals say, but watch out for larger openings.

The ice is never still. Massive pressure causes ruptures and elaborate combinations of paper-thin and rock-heavy layers protrude from the surface.

Baikal is known for extremely clear water.

It produces hundreds of different patterns of multi-layered cracks or bubbles.

On the rocky shore, winter creates elaborate ice sculptures of its own.

All photographs courtesy Oleg Boldyrev.