The earliest extant brick pagoda is the 40-metre-tall Songyue Pagoda in Dengfeng Country, Henan. This curved, circle-based pagoda was built in 523 during the Northern Wei Dynasty, and has survived for 15 centuries. Much like the later pagodas found during the following Tang Dynasty, this temple featured tiers of eaves encircling its frame, as well as a spire crowning the top. Its walls are 2.5 m thick, with a ground floor diameter of 10.6 m. Another early brick pagoda is the Sui Dynasty Guoqing Pagoda built in 597.