Russian 460 metre radio mast

The Russian 460 metres radio masts are among the most secret supertall structures ever built. Three such masts, which were developed by Stako, were erected in mid-1980s near Inta, Dudinka and Taymylyr as masts for the North Siberian Chayka Chain for transmitting navigation signals on 100 kHz with 1200 kW. All these masts are grounded lattice structures of tubular steel elements with triangular cross section.

Source: Wikipedia — Russian 460 metre radio mast (CC BY-SA 4.0)