Across from the site of the former Baharuddin Vocational Institute is Masjid Mujahidin which has the distinction of being the first mosque designed by the HDB. The mosque was the result of 11 years of hard work and planning by the Muslim community in Queenstown who came together to work with various agencies such as Majlis Ugama Islam Singapura (MUIS) and the HDB to build a mosque.
The mosque was completed at a cost of $800,000 with some funds raised by the community. It was officially opened by Dr. Ahmad Mattar, then Acting Minister for Social Affairs, on 9 October 1977.
In building this mosque, the HDB architects faced an unusual constraint. In line with Islamic principles, the rectangular prayer hall must face Mecca. However, it was difficult to do so as it was not possible to align the building to Mecca and the adjoining roads at the same time since it was a corner site. The architects finally hit on a clever solution by housing the rectangular hall in a circular building.