Margaret Island’s the thermal waters were brought to the surface in 1886. The island was opened to the public in 1869 but until 1900, when the connecting link with Margaret bridge was built, the only access was by boat. Baths were built on the island around the end of the 19th century to exploit the natural waters. In 1945 the island was declared a free public park for all citizens. Since then it has been one of the most popular recreational areas in Budapest.

The Grand Hotel Thermal on Margareth Island was built in neo-renessaince style in 1872 by the famous Hungarian architect, Miklos Ybl, who’s creation are among others the Hungarian Operahouse, and the Saint Stephen Basilica too. In 1926 a sanatory wing was added to the hotel. The medicinal waters of the local thermal springs enter the hotel’s hydrotherapy equipment at a temperature of 70′ C  (158′ F)  and are cooled down to 34’C (89’F), 36’C (91’F) and 40’C (104’F) while maintaining the active curative ingredients.