Bad Nauheim is located in the middle of Hesse, about 35km in the north of Frankfurt. Its surrounded by great nature but also plenty of culture. You can hike in Taunus or Vogelsberg (low mountain ranges), go shopping or visit museums in Frankfurt or visit many beautiful towns with great history. There is, for example Marburg (with castle and beautiful old town), Wetzlar (where Goethe has lived) only 30 min away. 1,5 -2 hours you arrive Weimar, Cologne or Heidelberg (very famous).
Bad Nauheim itself ist very beautiful too. You can get everything there, a swimming pool, mini-golf, golf, theatre, nice restaurants and bars, only 25-30 min footwalk away from my appartment through a lovely park. In former times it was very famous and kings and other famous people came here for their health. Also Elvis Presley lived here.