Hal Saflieni is an ancient underground necropolis located in the town of Paola, in the south of Malta. The site is composed of a series of chambers and passages excavated into the soft limestone bedrock, and is believed to have been used as a burial site from around 4000 BC to 2500 BC.

The most notable feature of Hal Saflieni is the so-called "Hypogeum," a large underground chamber with several smaller rooms branching off from it. The walls of the Hypogeum are decorated with intricate carvings and painted in shades of red ochre, suggesting that the site was used for more than just burial.

Today, the site is a popular tourist attraction, but only a limited number of visitors are allowed inside at any given time due to the fragility of the site. Guided tours are available, and visitors can learn about the history and significance of Hal Saflieni, as well as the techniques used to construct the underground complex.