spacecraft to land on another planet, Venus. In 1971, Mars 3 became the first spacecraft to land on Mars. During the same period, Lunokhod 1 became the first space exploration rover, while Salyut 1 became the world's first space station. Russia had 172 active satellites in space in April 2022, the world's third-highest. Tourism According to the World Tourism Organization, Russia was the sixteenth-most visited country in the world, and the tenth-most visited country in Europe, in 2018, with over 24.6 million visits. According to Federal Agency for Tourism, the number of inbound trips of foreign citizens to Russia amounted to 24.4 million in 2019. Russia's international tourism receipts in 2018 amounted to $11.6 billion. In 2019, travel and tourism accounted for about 4.8% of country's total GDP. Major tourist routes in Russia include a journey around the Golden Ring of Russia, a theme route of ancient Russian cities, cruises on large rivers such as the Volga, hikes on mountain ranges such as the Caucasus Mountains, and journeys on the famous Trans-Siberian Railway. Russia's most visited and popular landmarks include Red Square, the Peterhof Palace, the Kazan Kremlin, the Trinity Lavra of St. Sergius and Lake Baikal. Moscow, the nation's cosmopolitan capital and historic core, is a bustling megacity. It retains its classical and Soviet-era architecture; while boasting high art, world class ballet, and modern skyscrapers. Saint Petersburg, the Imperial capital, is famous for its classical architecture, cathedrals, museums and theatres, white nights, criss-crossing rivers and numerous canals. Russia is famed worldwide for its rich museums, such as the State Russian, the State Hermitage, and the Tretyakov Gallery; and for theatres such as the Bolshoi and the Mariinsky. The Moscow Kremlin and the Saint Basil's Cathedral are among the cultural landmarks of Russia. Demographics Russia is one of the world's most sparsely populated and urbanised countries, with the vast majority of its population concentrated within its western part. It had a population of 142.8 million according to the 2010 census, which rose to roughly 145.5 million as of 2022. Russia is the most populous country in Europe, and the world's ninth most populous country, with a population density of 9 inhabitants per square kilometre (23 per square mile). Since the 1990s, Russia's death rate has exceeded its birth rate, which some analysts have called a demographic crisis. In 2019, the total fertility rate across Russia was estimated to be 1.5