Pages like this one and this one and this one got me interested in the cold war antenna array known as the “Elephant Cage.” It was built by the US military in Udon Thani province, northeast Thailand, at an air force base used for signals intelligence back in the day, and suspected of housing a CIA black site in more recent years (although it is now apparently a mushroom farm/museum open to the public). Wikipedia describes the Elephant Cage as thus:
The AN/FLR-9 is a type of very large circular “Wullenweber” antenna array, built at eight locations during the cold war for HF/DF direction finding of high priority targets. The worldwide network, known collectively as “Iron Horse”, could locate HF communications almost anywhere on Earth. Because of the exceptionally large size of its outer reflecting screen (1056 vertical steel wires supported by 96 120-foot towers), the FLR-9 was commonly referred to by the nickname “Elephant Cage.”https://en.wikipedia.org/wiki/AN/FLR-9
None of the Elephant cages exist anymore, although parts of the one in Udon might still be found around town, if local stories are to be believed. I just wanted to compile all of the photos I’ve bookmarked in a single post.