Karaj is a large city, effectively a suburb of Tehran, but also the capital of Alborz province, 20km. west of Tehran, at the foothills of the Alborz mountains.
The earliest records of Karaj date back to the 30th century BC. The city was developed under the rule of the Safavid and Qajar dynasties and is home to historical buildings and memorials from those eras. Until the second half of the 20th century, it used to be known mainly as a summer resort. Today, it is a major industrial city, with factories producing sugar, textiles and wire.
Karaj has been hosting communities since 3000 years BC. The Khurvin region of Karaj has been inhabited since the Bronze Age and the Kelak region on the left bank of Karaj River since the Iron Age.
The stone-built Takht-e Rostam, located on a mount in the west of Shahriar County, was built in the Parthian era as a Zoroastrian fire temple.
Until the late 20th century, the city was mainly crossed into by a stone bridge built in the Safavid era. The stone-built Shah-Abbasi Caravansary, located at the southeast of Towhid Square, was built in the same era, under the rule of Shah Esmāil.
In the 1810s, the Palace of Soleymaniye, which included four towers surrounded by gardens and walls, was built as a summer resort by the order of Shahzaden Soleyman (Soleyman Mirza), an old prince governor of Kermānšāh. Granted in the Pahlavi era by Rezā Shah Pahlavi, it is now housing the Faculty of Agriculture of the University of Tehran.
The Morvārid Palace was constructed in the nearby Mehrshahr district, during the Pahlavi era. It was designed by the Frank Lloyd Wright Foundation (Taliesin Associated Architects) on instructions from Shams Pahlavi, elder sister of Mohammad Reza Pahlavi.