Between the 6th and the 14th centuries, successive Chăm rulers presided over an extraordinary flowering of Hindu art and architecture representing, in the view of many scholars, some of the finest that the region has ever produced. This flowering made use of the most sophisticated architectural techniques, which enabled the Chăm to construct their temples using advanced masonry technology.

Archaeological evidence shows that the surviving Chăm towers constitute but a fraction of what once existed in the region.

Việt Nam's oldest surviving Chăm vestiges, dating from the 7th and 8th century CE, are classified for architectural purposes as early Trà Kiệu or Mỹ Sơn E1 style (7th and 8th centuries); extant examples from this early ‘golden age’ of Chăm architecture include the Mỹ Sơn E1 and F1 and Phú Hải towers.

From the late 8th century onwards Champa became increasingly subservient to Angkor, and as a result Khmer architectural influence began to make itself felt in the construction of the Chăm temple-towers. However, whilst the so-called Hòa Lai style (late 8th-early 9th centuries) which evolved during this period was characterised by the appearance of tiered towers akin to the contemporaneous Khmer prasat, the sturdiness of design, elegant pilasters and carved, vaulted doors of the surviving structures - Hòa Lai, Pô Đam and Mỹ Sơn A'1, A'2, A'3, C7 and F3 - gave them a beauty which was uniquely Chăm in conception.

In the latter half of the 9th century King Indravarman II transferred his capital to Đồng Dương, constructing a large Buddhist monastery or vihara at that site with the aim of propagating a new mixed Hindu-Buddhist faith. Expressed through the architecture of Mỹ Sơn A10 and B4 and the temples constructed at Đồng Dương, the so-called Đồng Dương style (late 9th-early 10th century) which emerged at this time was characterised by a new emphasis on grandeur. Many magnificent Chăm Buddhist statues and sculptures date from this era.

However, at the start of the 10th century Indravarman III restored Hinduism to its former status as the national religion of Champa and once again made Trà Kiệu and Mỹ Sơn the political and religious centres of the kingdom. Close relations were subsequently developed with the Javanese, leading to the application of the latest Javanese architectural ideas in the design of Chăm temple-towers. The result was the elegant Mỹ Sơn A1 style (10th century), which is regarded by many scholars as the pinnacle of Chăm architectural development; examples of this style include Khương Mỹ, the north-westernmost temple of the Pô Nagar complex, and Mỹ Sơn A1, B2, B3, B5, B6, B8, C1, C2, C3, C4, C5, C6, D1, D2 and D4.

That main sanctuary contains a linga-yoni (phallic representation) of the god Shiva set on a dias, from which holy water was traditionally channelled for use in purification rituals. Since the kalan was a sacred place it is believed that only Brahmans who had studied the sacred teachings were permitted to enter and carry out rituals there.

There has been considerable debate amongst scholars regarding the way in which the Chăm towers were constructed, since neither cracks nor any type of mortar have been found between the bricks. One somewhat unlikely theory holds that the towers were built with half-baked bricks and that the entire edifice was subsequently burned to harden the bricks in a way which guaranteed that they bonded together tightly and solidly. Another suggests that some kind of natural resin was used to bind the bricks together. A further mystery is how Chăm builders managed to lift the collossal stone blocks used to construct the door frames and tower tops.