Rustaq was once the capital of Oman, and you can still see many traces of its historical legacy. In a city of low buildings, most no taller than the palm trees which abound here, the pre-Islamic-era Rustaq Fort makes a majestic sight. Its thick walls enclose a mosque long known as a center of Islamic learning. Al-Hazm Castle is built in a similarly monumental style, though it dates from more than a millennium later.
The wadis (valleys) of the surrounding area are well worth exploring and are known for their natural springs: Al-Kasfa is the most popular place to enjoy the therapeutic properties of the warm, sulfurous waters. Natural irrigation makes this a fertile fruit-growing region which is also known for its excellent honey.
Rustaq (or Ar-Rustaq), is in the Hajar Mountains about 100 miles (160 kilometers) west of Muscat. It can be easily combined with a trip to nearby Jebal Akhdar.