In March 2016, Binh Son tower was named National Treasure. Binh Son Tower is a hollow tower, the body is structured with two layers of bricks: bearing brick has many sizes to be smooth, used for building pedestal, built inside the tower, and stepped up as a stratified roof. Most of the aperture bricks are structured with a mortise pin, shaped to match each layer, each floor, and then solidly fired to build, ensuring tight bonding and great bearing capacity. Outside, the tower is covered with a layer of square bricks, each side is 0.46m long, covering the tower body. The exterior of this tile has a rich pattern of decorations. Various styles of patterns depend on the location of each floor but design a project to decorate each side of the tower, shape each brick with complete patterns, then mark the brick according to the position before being fired. recent surveys and studies show that the bricks used to build Binh Son tower are burned with high fire. In order for the bricks to stand together at a vertical height without lime and mortar, the tower builders invented quite unique assembly methods. The brick is made with edges and edges just to hold each other, that is the method of building a brick at the base of the pedestal. There is another way that each brick has a trapezoidal hole, two bricks are arranged close together, forming a fish dream and people pour lead into that fish dream to hold the 2 bricks together, that is the method of building with fish. lead is used to erect the base of the tower.nIt is said that this is the tower built by the Cham people. In the past, this could be the place where Chiem Thanh prisoners were kept. The prisoners were released to live in villages, then built temples and built this tower. Many Cham towers in the South and this tower have similarities. And scientists in our country said that this tower appeared in the Ly dynasty and was restored and embellished in the Tran dynasty. Despite influencing many Cham cultures, the tower is created and built by the hands and ideas of the Vietnamese in the Ly - Tran dynasty. In the Ly dynasty, many works in the North also had an influence on Cham culture, not just this tower.nIn the early 1960s, the Lo river dike broke, flooded, and eroded at the base of the tower, so the tilted Binh Son tower was in danger of collapsing. When the top of the tower fell and some roofs were broken, the Department of Culture of Vinh Phuc at that time and the Ministry of Culture decided to restore it. The reconstruction of the tower took place in 1972, in the midst of a fierce war. Each brick is dismantled, marked, plastered to restore like the real thing. The artisan of the land of Huong Canh was mobilized to create bricks with dream, complex patterns exactly like the original, to supplement the broken ones. They have to use the red soil taken from the Vuon Sui mound to prevent shrinkage, use green clay in Dam Mat to have cohesion and smooth the face, use soil from Mong Trau as the main material, to form a compound for making flower bricks. Van Cau Ly period. According to recorded history, on average, for every 100 carpentry bricks, one can be selected with the right sample and baked with 48 straw of the same pattern, to choose a qualified member. As for making bricks to supplement the broken ones, it also takes 2 years and takes tens of thousands of carpentry bricks.