Along a riverside road that connects Panaji to Old Goa, one passes across the town of Ribandar. Along this scenic road is a long stone wall along the road. At one point, there is a cross within an enclosed structure that faces the Mandovi River.

The area behind the wall was once a gunpowder factory called Casa de Polvora. It was built by the then Viceroy Dom Francisco da Gama. According to historical sources, the factory was used to produce three types of gunpowder: warfare, pyrotechnics, and hunting.

Gunpowder was an important tool for the Portuguese. It was one of the first of its kind in Asia and was used to supply gunpowder to the other Portuguese colonies during that era.

The factory was brought to Goa in the early 16th century. It was shifted to a few places and was eventually set up at Panelim in Ribandar by the Portuguese in 1630. Later, it was shut down by the Decree of  November 25, 1869. Today, the millstones from this gunpowder factory are on display at Old Goa, a short distance away.