Budapest is the capital and the most populous city of Hungary, and the tenth-largest city in the European Union by population within city limits. Budapest is both a city and county, and forms the centre of the Budapest metropolitan area, which has an area of 7,626 square kilometres and a population of 3,303,786, comprising 33 percent of the population of Hungary.

The history of Budapest began when an early Celtic settlement transformed into the Roman town of Aquincum, the capital of Lower Pannonia. The Hungarians arrived in the territory in the late 9th century. Buda, the settlements on the west bank of the river, became one of the centres of Renaissance humanist culture by the 15th century. Pest-Buda became a global city with the unification of Buda, Óbuda, and Pest on 17 November 1873, with the name 'Budapest' given to the new capital. Budapest also became the co-capital of the Austro-Hungarian Empire, a great power that dissolved in 1918, following World War I. The city was the focal point of the Hungarian Revolution of 1848, the Battle of Budapest in 1945, and the Hungarian Revolution of 1956.

Budapest is an Alpha − global city with strengths in commerce, finance, media, art, fashion, research, technology, education, and entertainment. It is Hungary's financial centre and the highest ranked Central and Eastern European city on Innovation Cities Top 100 index, as well ranked as the second fastest-developing urban economy in Europe. Budapest is the headquarters of the European Institute of Innovation and Technology, the European Police College and the first foreign office of the China Investment Promotion Agency.

Budapest is cited as one of the most beautiful cities in Europe, ranked as "the world's second best city" by Condé Nast Traveler, and "Europe's 7th most idyllic place to live" by Forbes. Among Budapest's important museums and cultural institutions is the Museum of Fine Arts. Further famous cultural institutions are the Hungarian National Museum, House of Terror, Franz Liszt Academy of Music, Hungarian State Opera House and National Széchényi Library. The central area of the city along the Danube River is classified as a UNESCO World Heritage Site and has many notable monuments, including the Hungarian Parliament, Buda Castle, Fisherman's Bastion, Gresham Palace, Széchenyi Chain Bridge, Matthias Church and the Liberty Statue. Budapest attracts 4.4 million international tourists per year, making it a popular destination in Europe.