Officially, Alexander I died of typhus aged 47 on 1 December 1825, but evidence suggests he faked his demise and lived as a holy man.
New handwriting analysis suggests Royal's death was faked so he could repent his sins as holy man.
One of the great sights for early travellers across Russia on the Trans-Siberian Railway after its opening in 1899.
One of the first stone buildings in Novosibirsk, the cathedral stands at the very beginning of its main street, Krasniy Prospect.
Built in the neo-Byzantine style with a gilded dome, it is named after one of the giants of Russian medieval history, but was also a monument to Tsar Alexander III, who initiated construction of the railway and the establishment of a station at Novonikolayevsk, as the city was then known, and donated the land and the money for the building.
Oldest torchbearer of any Olympic relay, he had lost his father in the Siege of Leningrad.
Rare historic pictures show Russia's last tsar as the first builder of the Trans-Siberian Railway 125 years ago this month.
Grand Duke Georgy Romanov will now promote Russian business in the EU.
Popular with the aristocracy and the royals in the 18th and 19th centuries, the lavish festivity will be held for tourists.