Tales of the Romanovs, and the decadence and opulence of Russia's architecture have immortalised the country in books and movies such as Anna Karenina. And now, the country is becoming immortalised as one of the fastest-growing river cruise destinations. The popularity of Russia's rivers has increased exponentially, especially over the past five years and more especially among Aussies. Viking River Cruises, which has been sailing in the region for 20 years, is seeing an increase in the number of Australians booking cruises within Russia. "Absolutely, we've seen an increase in Australians booking the Russia river itinerary year on year, and longer term over the past five years," a Viking Cruises spokesperson said. Aside from local Russian lines, Uniworld, Evergreen and APT also sail in Russia and, like Viking, cruise to the heart of the country on larger-than-average ships. Viking, which is one of the larger operators in Russia, has four ships on the Volga, Neva and Svir rivers. Viking's Russian fleet includes the Viking Akun, Helgi, Ingvar and Truvor. "One itinerary on the rivers of Russia, however, remains one of the most popular sailings amongst Australians. The 13-day Waterways of the Tsars itinerary sails between Moscow and St Petersburg between May and October," said the Viking spokesperson. APT has revealed its 2020 Russian itineraries have almost sold out. "For 2020 we are operating three Russia river cruises, which are almost sold out. In 2021, we also have three departures ... Our Russia cruises are very popular with solo travellers," an APT representative said. Meanwhile, Cruise &amp; Maritime Voyages is launching its biggest 2021 European summer season with buy-one-get-one-free fares, including cruises on its newest addition to the fleet, Amy Johnson. This will be CMV's biggest launch to date, with 166 cruises on sale. It will also be the largest-ever release of solo cabins across a CMV season, with over 15 per cent of CMV's fleet capacity dedicated to solo travellers since the addition of 146 single cabins on Amy Johnson. The 2021 European Summer Season focuses on popular Northern European destinations on a range of newly developed itineraries. There will be a record four CMV ships visiting the Arctic and Iceland during summer. The line will also be making maiden calls to unusual destinations such as Roseau in Dominica; the mountainous island Runavik in the Faroes; and the ancient metropolis of Constanta, Romania's oldest seaport. Regular cruise favourites, including sailings to the Norwegian Fjords, the Baltics and around Britain, will continue to feature.