Mainz is the capital and largest city of Rhineland-Palatinate, Germany.

Most of the city is upstream of the Rhine before it flows west. The north of the city faces Wiesbaden, in Hesse, and the east the confluence of the Main.

Mainz is an independent city with a population of 218,578 (as of 2019) and forms part of the Frankfurt Rhine-Main Metropolitan Region.

Mainz was founded by the Romans in the 1st century BC as a military fortress on the northernmost frontier of the empire and provincial capital of Germania Superior. Mainz became an important city in the 8th century AD as part of the Holy Roman Empire, capital of the Electorate of Mainz and seat of the Archbishop-Elector of Mainz, the Primate of Germany. Mainz is famous as the home of Johannes Gutenberg, the inventor of the movable-type printing press, who in the early 1450s manufactured his first books in the city, including the Gutenberg Bible. Mainz was heavily damaged in World War II; more than 30 air raids destroyed most of the historic buildings.

Mainz is notable as a transport hub, for wine production, and for its many rebuilt historic buildings.

Main sights include:

• Romano-Germanic Central Museum. It is home to Roman, Medieval, and earlier artifacts.
• Museum of Ancient Seafaring. It houses the remains of five Roman boats from the late 4th century, discovered in the 1980s.
• Roman remains, including Jupiter's column, Drusus' mausoleum, the ruins of the theatre and the aqueduct.
• Mainz Cathedral of St. Martin (Mainzer Dom), over 1,000 years old.
• St. John's Church, 7th-century church building
• Staatstheater Mainz
• The Iron Tower (Eisenturm, tower at the former iron market), a 13th-century gate-tower.
• The Wood Tower (Holzturm, tower at the former wood market), a 15th-century gate tower.
• The Gutenberg Museum - exhibits an original Gutenberg Bible amongst many other printed books from the 15th century and later.
• The Mainz Old Town - what's left of it, the quarter south of the cathedral survived World War II.
• The old arsenal, the central arsenal of the fortress Mainz during the 17th and 18th century
• The Electoral Palace, residence of the prince-elector.
• The Marktbrunnen, one of the largest Renaissance fountains in Germany.
• Domus Universitatis (1615), for centuries the tallest edifice in Mainz.
• Christ Church, built 1898-1903, bombed in 1945 and rebuilt in 1948-1954.
• The Church of St. Stephan, with post-war windows by Marc Chagall.
• Citadel.
• The ruins of the church St. Christoph, a World War II memorial
• Schönborner Hof (1668).
• Rococo churches of St. Augustin (the Augustinerkirche, Mainz) and St. Peter (the Peterskirche, Mainz).
• Churches of St. Ignatius (1763) and St. Quintin.
• Erthaler Hof (1743)
• The Baroque Bassenheimer Hof (1750)
• The Botanischer Garten der Johannes Gutenberg-Universitat Mainz, a botanical garden maintained by the university
• Landesmuseum Mainz, state museum with archaeology and art.
• Zweites Deutsches Fernsehen (ZDF) - one of the largest public German TV-Broadcaster.
• New synagogue in Mainz
• Kunsthalle Mainz - museum for contemporary art