The most famous prehistoric site of the Maltese archipelago are the Ggantija Temples of ix-Xaghra from the third millennium BC. It was the first of the Maltese prehistoric monuments to be cleared of earth and debris and the operation was undertaken by Lieutenant-Colonel John Otto-Bayer, at his own expense, when he was the Chief Civil Officer of Gozo (1819-1826).

Lying on the south eastern slope of the village over looking ir-Ramla valley, the complex consists of two temple units enclosed by a single outer wall. The Temples are separate and each has a single entrance on a common façade in front of which there is a very extensive plaza. They are built of massive stones quarried on the spot and on a five-apse plan — the plan refers to the goddess, that is the head, the shoulders and arms, and the legs folded beneath the thighs.

The South Temple, dating from about 3600 BC, is manifestly the older of the two, as well as the larger and better preserved. The entrance is over a huge flat treshold slab. In the first pair of apses, to the right, there are two rectangular altars, the left one still preserving traces spiral decorations. The second pair of apses on a slightly higher level are larger. In the left apse there are three niches complete with capstones; a symbol of the goddess. These niches were flanked by a phallic symbol on the right and a slab with a long relief carving of a snake on the left — preserved at the Museum of Archaeology. Both suggest that fertility rites took place in this particular apse.

In the right apse, there are the remains of a fire-reddened circular stone hearth, possibly for an eternal flame, as well as the remains of what was probably a small enclosure from where oracles were delivered. The larger apse at the rear of the temple is on an even higher level, the high threshold presenting a pitted pattern on the outer face. The visitor is bound to remain spellbound by the sheer size and imposing height of the surviving remains. The cornerstones and rear wall of the South Temple are simply impressive. One massive stone weighs some seventy metric tonnes and this has led to the belief that the temple was built by giants.
The North Temple, built over one thousand years later, is considerably smaller but with a more evolved four-apse plan having its rear apse replaced by a shallow niche. The entance is very similar to that of the first temple, only the threshold is narrower and shorter.

A Guinness Book of Records entry confirms these Temples as "the oldest free standing structures in the world".