Warsaw, officially the Capital City of Warsaw, is the capital and largest city of Poland. The metropolis stands on the River Vistula in east-central Poland. Its population is officially estimated at 1.86 million residents within a greater metropolitan area of 3.27 million residents, which makes Warsaw the 7th most-populous city in the European Union. The city area measures 517 km2 (200 sq mi) and comprises 18 districts, while the metropolitan area covers 6,100 km2 (2,355 sq mi). Warsaw is classified as an alpha global city, a major cultural, political and economic hub, and the country's seat of government. It is also the capital of the Masovian Voivodeship.

Warsaw traces its origins to a small fishing town in Masovia. The city rose to prominence in the late 16th century, when Sigismund III decided to move the Polish capital and his royal court from Kraków. Warsaw served as the de facto capital of the Polish–Lithuanian Commonwealth until 1795, and subsequently as the seat of Napoleon's Duchy of Warsaw. The 19th century and its Industrial Revolution brought a demographic boom, which made it one of the largest and most densely populated cities in Europe. Known then for its elegant architecture and boulevards, Warsaw was bombed and besieged at the start of World War II in 1939. Much of the historic city was destroyed and its diverse population decimated by the Ghetto Uprising in 1943, the general Warsaw Uprising in 1944, and systematic razing.

Warsaw is served by three international airports, the busiest being Warsaw Chopin, as well as Warsaw Modlin and Warsaw Radom Airport. Major public transport services operating in the city include the Warsaw Metro, buses, commuter rail service and an extensive tram network. The city is a significant economic centre for the region, with the Warsaw Stock Exchange being the largest in Central and Eastern Europe. It is the base for Frontex, the European Union agency for external border security, and ODIHR, one of the principal institutions of the Organization for Security and Co-operation in Europe. Warsaw has one of Europe's highest concentrations of skyscrapers, and the Varso Place is the tallest building in the European Union.

The city's primary educational and cultural institutions comprise the University of Warsaw, the Warsaw University of Technology, the SGH Warsaw School of Economics, the Chopin University of Music, the Polish Academy of Sciences, the National Philharmonic Orchestra, the National Museum, and the Warsaw Grand Theatre, the largest of its kind in the world. The reconstructed Old Town, which represents a variety of European architectural styles, was listed as a World Heritage Site in 1980. Other landmarks include the Royal Castle, Sigismund's Column, the Wilanów Palace, the Palace on the Isle, St. John's Archcathedral, Main Market Square, and numerous churches and mansions along the Royal Route. Warsaw is a green capital, with around a quarter of the city's area occupied by parks. In sports, the city is home to Legia Warsaw football club and hosts the annual Warsaw Marathon.