Kyiv, also spelled Kiev, is the capital and most populous city of Ukraine. It is in north-central Ukraine along the Dnieper River. As of 1 January 2022, its population was 2,952,301, making Kyiv the seventh-most populous city in Europe. Kyiv is an important industrial, scientific, educational, and cultural center in Eastern Europe. It is home to many high-tech industries, higher education institutions, and historical landmarks. The city has an extensive system of public transport and infrastructure, including the Kyiv Metro. The city's name is said to derive from the name of Kyi, one of its four legendary founders. During its history, Kyiv, one of the oldest cities in Eastern Europe, passed through several stages of prominence and obscurity. The city probably existed as a commercial center as early as the 5th century. A Slavic settlement on the great trade route between Scandinavia and Constantinople, Kyiv was a tributary of the Khazars, until its capture by the Varangians (Vikings) in the mid-9th century. Following the collapse of the Soviet Union and Ukrainian independence in 1991, Kyiv remained Ukraine's capital and experienced a steady influx of ethnic Ukrainian migrants from other regions of the country. During the country's transformation to a market economy and electoral democracy, Kyiv has continued to be Ukraine's largest and wealthiest city. After UEFA Euro 2012, the city became the most popular destination for European tourists. A record number of 1.8 million foreign tourists was registered then along with about 2.5 million domestic tourists. More than 850,000 foreign tourists visited Kyiv in the first half of 2018, as compared to 660,000 tourists over the same period in 2013.