Anaconda Smelter, Montana, 1969.
“The Anaconda Smelter Stack is the tallest surviving masonry struct

Anaconda Smelter, Montana, 1969.
“The Anaconda Smelter Stack is the tallest surviving masonry structure in the world, with an overall height of about 585 feet (178.3 m), including a brick chimney 555 feet (169.2 m) tall and the downhill side of a concrete foundation 30 feet (9.1 m) tall.[2][3][A] It is a brick smoke stack or chimney, built in 1918 as part of the Washoe Smelter of the Anaconda Copper Mining Company (ACM) at Anaconda, Montana, in the United States. A terra cotta coating covered the entire brick chimney when new, but by the time the smelter closed in 1981, most had eroded away except for the upper 40%, exposing most of its bricks and reinforcing rods. The inside diameter at the bottom of the brick chimney is 76 feet (23.2 m) while that at the top is about 60 feet (18.3 m). The stack and its viewing area are now the two-part Anaconda Smoke Stack State Park” Wikipedia
The height of the smelter stack meant that the numerous pollutants emitted through it, most importantly sulphur dioxide, were dispersed over a sizable portion of south central Montana. Though it is a considerable distance from the highway, thanks to its height the now unused stack can be seen from I-90 between Butte and Deer Lodge, -- source link

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