Complex sentence: The mountain features a United States Forest Service fire lookout tower with an steel tower, which was built on the summit of Yamsay in 1929, but removed after the 1970s and only remnants of the foundation remain today.
Split into simpler sentences: The mountain features a United States Forest Service fire lookout tower with an steel tower, built on the summit of Yamsay in 1929. It was removed after the 1970s, and only remnants of the foundation remain today.