Facebook has PTR records for its IP addresses, ending with the #IATA airport code. For instance 18.104.22.168 returns edge-star-mini-shv-01-eze1.facebook.com with EZE = Buenos Aires.
Except that 22.214.171.124 returned (it is now deleted) edge-star-mini-shv-01-lht6.facebook.com. There is no code LHT. Which airport can it be (probably in South America)?
Vive les gougères ! mnt-by: @yapret @papaeng89