Austria.

Vienna is a beautiful city located in Austria and a country full of history and culture. Vienna is the capital of Austria and the center of European culture, with many world-renowned artistic and cultural heritages.

The history of Vienna can be traced back to the 15th century BC, when it was a small village, and later developed into an important European city. Vienna has a long history and culture and is home to many world-renowned artistic and cultural heritages, such as the Vienna State Opera, the Vienna State Museum, the Vienna State Library, and the Vienna State Gallery.

Vienna is also a prosperous business center, with many internationally renowned enterprises, such as the United Nations headquarters, the World Bank, the International Monetary Fund and so on. Vienna is also an international financial center with many international financial institutions such as the European Central Bank, the European Investment Bank, and the European Central Bank.

Vienna's hydrology

Vienna's rivers and lakes cover an area*** of 19.1km?, which is 4.6% of Vienna's area, second only to Burgenland. The Danube is Vienna's main river, the length of the river is the second longest in Europe after the Volga. It originates on the eastern slopes of the Black Forest Mountains in southwestern Germany and flows from west to east through Austria, Slovakia, Hungary, Croatia, Serbia, Bulgaria, Romania, Ukraine, and empties into the Black Sea in south-central Ukraine.

It flows through nine countries, is the world's main stream flows through the most countries of the river. The tributary Ting extends to Switzerland, Poland, Italy, Bosnia and Herzegovina, the Czech Republic, and Slovenia and Moldova **** 7 countries, and finally in the eastern part of Romania Sulina into the Black Sea. The Danube River is 2850 kilometers long, with a basin area of 817,000 square kilometers, an average annual flow of 6430 cubic meters per second at the mouth of the river, and an average multi-year runoff of 203 billion cubic meters.

Reference for the above: Baidu Encyclopedia-Vienna