The Ruins of St. Paul, standing like a cardboard pop-up on a hilltop, are arguably the region's most famous tourist site. The Cathedral of Saint Paul was a 16th-century cathedral built from 1582 to 1602 and dedicated to Saint Paul the apostle of Jesus.

The stone facade, which features carvings relating the story of the Catholic Church in Asia (complete with some dragons and a sailing ship), is all that remains of the Jesuit church after a fire during a typhoon ripped through it in 1835.

You’ll see through glass walkways a glimpse at the stone foundations. An old restored crypt contains a Museum of Sacred Art. You’ll want to note the portion of the Old City Wall, running behind the ruins, dating back to 1569, formed from a mixture of clay, soil, sand, glutinous rice, crushed rocks and oyster shells.

Built by the Jesuits, the Cathedral was the largest Catholic church in Asia at the time; and the royalty of Europe competed with each other to give the Cathedral the best gifts. The Fortaleza do Monte overlooks the ruin.

The ruins now consist of the southern stone facade - intricately carved by Japanese Christians in exile from their homeland - and the crypts of the Jesuits who established and maintained the Cathedral. The facade sits on a small hill, with 66 stone steps leading up to it.

The carvings include Jesuit images with Oriental themes, including one of a woman stepping on a seven-headed hydra, described by Chinese characters as 'the Holy Mother tramples the heads of the dragon'. Other engravings include those of the founders of the Jesuit Order, the conquest of Death by Jesus, and others, all topped by a dove with wings outstretched.

Fom 1990 to 1995 the ruins were excavated to study its historic past. The ruins were restored by the Macanese government into a museum, and the facade is now buttressed with concrete and steel in a way which preserves the aesthetic integrity of the facade. A steel stairway allows tourists to climb up to the top of the facade from the rear.

It is customary to throw coins into the top window of the ruins from the stairs, for luck.
Since 2005, the ruins have been protected as part of the Historic Centre of Macau, a UNESCO World Heritage Site.