From Wikipedia:

A-Ma Temple, situated on the southwest tip of the Macau Peninsula, is one of the oldest and most famous temples in Macau. Built in 1488, the temple is dedicated to the goddess of seafarers and fishermen Matsu.

The name Macau is thought to be derived from the name of the temple. It is said that when the Portuguese sailors landed at the coast just outside the temple and asked the name of the place, the natives replied "媽閣" (Jyutping: "Maa1 Gok3"). The Portuguese then named the peninsula "Macao".  The temple was well described in ancient Chinese texts, as well as represented in paintings. It is also one of the first scenes photographed in China.

In 2005, the temple became one of the designated sites of the Historic Centre of Macau enlisted on UNESCO World Heritage List.