Mykolaiv is a port city on the Black Sea in southern Ukraine. It's known for its shipbuilding and naval industries, and is also a popular tourist destination. The city's historical center is home to a variety of architecture, ranging from Gothic churches to Art Nouveau buildings. Mykolaiv's main landmark is the 18th-century Mykolaiv Castle, which now houses the Regional Museum. Other popular attractions include the Pivdennyi (Southern) Bridge, which spans the Dnieper River, and the Shipbuilding Museum, which showcases the city's maritime history.