Budapest, Hungary is famous for its thermal baths and spas, which have been used for centuries for their therapeutic properties. Some of the most popular thermal baths in Budapest include:

1. Gellért Baths: This historic bath is housed in a stunning Art Nouveau building and is known for its therapeutic waters, massages, and scenic views of the city.

2. Rudas Baths: This Turkish-style bath dates back to the 16th century and is known for its octagonal pool, thermal waters, and rooftop terrace with panoramic views.

3. Széchenyi Baths: The largest thermal bath complex in Budapest, Széchenyi Baths offers several indoor and outdoor pools, including a relaxing wave pool and a thermal pool.

4. Lukács Baths: This historic bath is known for its traditional Hungarian thermal waters and is popular among locals.

5. Rác Baths: This small bathhouse is known for its intimate atmosphere and traditional thermal waters.

These are just a few of the many thermal baths in Budapest, each offering its own unique atmosphere and set of services. It's a good idea to research and compare the different options to find the one that best suits your needs and preferences.