Drone footage shows long queues of vehicles on the way to exit Russia on its border with Georgia, in Verkhny Lars, Russia, September 26, 2022, in this still image obtained from a video. The Insider/Handout via REUTERS

ALMATY, Oct 5 (Reuters) - For the men leaving Russia after vast journeys across the world's biggest country, there is now often a final ordeal: visceral fear at the border followed by a rush of relief for those who reach the other side.

Hundreds of thousands of men have left Russia since President Vladimir Putin invaded Ukraine on Feb. 24. Some feared they would be called up to fight, others simply sought new lives after war changed Russia more dramatically than at any time since the 1991 collapse of the Soviet Union.

After Putin announced a partial mobilisation of reservists last month, Russia's first since World War Two, the trickle of emigres turned into a flood - and mundane border anxiety turned into fear for thousands of men who rushed to the exits.

Publisher Aidar Buribayev started thinking about leaving immediately after Putin announced the mobilisation on Sept. 21. What finally convinced him was seeing Moscow, for centuries a crucible of raw, bustling energy, so subdued and deserted.

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"The final straw was driving through Moscow and suddenly realising there were no traffic jams, and seeing my co-working office almost empty," Buribayev, the publisher of Russian online news outlet MediaLeaks.ru, told Reuters in Kazakhstan.

Thus began a 4,300 km (2,700 mile) odyssey out of Russia, a pivotal break with his homeland that is shaping the lives of entire generations of urban Russians and their families.