Yakutsk is the answer to a quiz question: the coldest city of more than 200,000 people on Earth. January averages -36.9°C according to the WMO 1991-2020 normals, with a daily high of -34°C, and the record is -64.4°C in February 1891. But the more interesting fact is underneath. The city stands on continuous permafrost, so buildings sit on piles and heating pipes run above the street. It began in 1632 as a Cossack fort built by Pyotr Beketov on the right bank of the Lena, 70 km downstream, and moved to its present site in 1642.
It isn't a pretty city. Most of the center is Soviet blocks, a few rebuilt wooden streets and a lot of murals. What you come for is inside and outside it: a museum of mammoths, a treasury of diamonds, a research lab dug into 10,000-year-old frozen ground, a street market where fish stand frozen on their tails, and the Sakha people (called Yakuts in Russian), who make up 55% of the republic and still have their own language, epic poems and horse culture. It's also a hard and expensive trip. Five days works because three go to the city and its surroundings, one to the Lena Pillars, and one is slack for the fog that regularly grounds flights in winter.
The plan is organized by place. Day one is the Treasury and the Old Town, day two the mammoths, the permafrost lab and the market, day three the ethnographic complexes and the ice cave on the Vilyuisky road, day four the Lena Pillars (UNESCO, 2012), and day five the zoo, the art museum and an evening at the theater. Start on a Monday: the Treasury is open weekdays only and the permafrost lab takes visitors only on weekdays by appointment. For the other end of the Siberian cold, see 5 Days in Irkutsk, about 1,400 km southwest on Lake Baikal, and for the country as a whole Russia. Read the entry and government-advice tips below before you book anything.