Sandomierz Cellars, Underground museum beneath Market Square in Sandomierz, Poland.

The Sandomierz Cellars tourist route links 34 former merchant cellars and warehouses from the 14th and 15th centuries, lying 4 to 12 metres below the surface. Its 470-metre path runs beneath buildings at Opatowska 1 and 2, Rynek 5 to 10, and the streets Oleśnickich, Opatowska, Bartolona and Rynek. Visitors enter at Rynek 10 (side entrance from Oleśnickich Street) and leave through the Town Hall. Some rooms keep their original brickwork and hold displays on the city's history and crafts.

The cellars began in medieval times when merchants started carving storage space beneath their houses. Over centuries they were expanded and modified, until opening as a museum in 1977 to preserve their commercial heritage.

The cellars are the 14th- and 15th-century merchant storerooms and warehouses of Sandomierz, partly with their original brickwork intact. Some chambers hold displays on the city's history, daily life and crafts, and guides recount local legends, notably that of Halina Krępianka saving the town from the Tatars in the 13th century.

The route is open all year and every day, and visits take place in groups led by a guide. The entrance is at Rynek 10 (side entrance from Oleśnickich Street), and the exit is in the Town Hall building. The 470-metre route runs 4 to 12 metres below the surface.

The route's creation was prompted by ground collapses and building disasters in Sandomierz in the 1960s. In 1963, a team from the AGH University of Science and Technology in Kraków designed a programme to save the Old Town, and mining works by the Bytom Mining Works began the following year. These works uncovered the multi-storey cellars, and some chambers were removed for structural reasons while the rest became the tourist route.