Among the various churches in Old Goa, there is a large collection of ruins near the western side of the historic site. Half a church spire rises into the sky, towering over the lush green surroundings. All around the tower are crumbling arches, stone walls, and ruins of what was once one of the largest churches in Goa.

These are the ruins of the Church of St. Augustine, which was built between 1597 and 1602 by Augustinian Friars who landed in Goa in 1587. It was considered one of the three great Augustinian churches in the Iberian world, the other two being The Basilica of the Escorial in Spain and St. Vincente de Fora in Lisbon.

The massive complex had eight chapels, four altars, a convent, and four towers. Over the years, the church was abandoned in 1835 and eventually fell into ruins. Today, out of the four towers, only a portion of one tower remains, which is also popularly called St. Augustine's Tower. The tower is 150 feet (46 meters) in height. As the structure crumbled over time, the artifacts were shifted elsewhere. The bell of the church was initially transferred to Fort Aguada and then later to Our Lady of the Immaculate Conception Church in Panaji.

In recent times, the relics of the Georgian Queen St. Ketevan the Martyr were discovered at this site by Indian and Georgian authorities.

The ruins are extremely fascinating to visit. One can see several ledger stones (inscribed stone slabs) on the floor. There are ornate, mysterious inscriptions on the crumbling red and brown walls. The ruins speak of a bygone era from the pages of history.