After Islam, the popularity of mystics (tasawwuf), as well as the prominence of tradition (Hadith), religious jurisprudence (fiqh), and philosophy in Qazvin, led to the emergence of many mosques and religious schools. They include:  About south-west of Qazvin are the tombs of two Saljuki era princes — "Abu Saeed Bijar", son of Sa'd, and "Abu Mansur Iltai", son of Takin — located in two separate towers known as the Kharraqan twin towers. Constructed in 1067 CE, these were the first monuments in Islamic architecture to include a non-conic two-layered dome. Both towers were severely damaged by a devastating earthquake in March 2003. Sepah Street (خیابان سپه , pronounced "Cepah" referring to ancient Persian army and not the revolutionary guards pronounced "Sipaahe") is known as the first modern street in Iran. This street entirely is carpeted with carved gray stone and is surrounded by craftsmen gift shops (used to be bars or bygone liquorshops, called May'kadeh) and hosts historical places such as Qazvin's Ali Qapu gate, entrance of Jame' Atiq mosque and historical schools. Qazvin has three buildings built by Russians in the late 19th/early 20th century. Among these is the current Mayor's office (former Ballet Hall) and a water reservoir. Nicholas church was built in 1904 by the Russian Company for Roads in Persia which had its headquarter here. The church was in use until being decommissioned in 1984 because the community of Russian emigres in Qazvin did not exist any more. The iconostasis and bell was removed to Tehran and the building handed over to the Iranian government which keeps it available to the public as a historic monument. In front of the church is a 1906 memorial to a Russian road engineer. Qazvin today is a center of textile trade, including cotton, silk and velvet, in addition to leather. It is on the railroad line and the highway between Tehran and Tabriz. Qazvin has one of the largest power plants feeding electricity into Iran's national power grid, the "Shahid Raja'i" facility, which provides 7% of Iran's electrical power. Qazvin has several institutes of higher education:   Some famous residential towers are: Punak (536 units), Aseman, Elahieh, Bademestan (440 units in 17 floors) and Tejarat tower with 28 floors.