D-Link announces two new additions to its family of connectivity solutions. The new 5km long-range Wireless AC Bridge (DAP-3711) and 20km Long Range Wireless AC Bridge (DAP-3712) are designed to offer... D‑Link unveils high‑speed, up to 20 km long‑range wireless bridges
"In standard atmospheric conditions, for an observer with eye level above sea level by 1.70 metres (5 ft 7 in), the horizon is at a distance of about 5 kilometres." I imagine that for 20km you'd have to stick that on a very tall building, or pole. Maybe less tall if on both sides. But still, 20km wireless? My home router can barely go through a wall!
Ubiquity gear can say things about all the above. Longest we managed to connect to an AP was 11,7 KM, on a sea shore region. Not the best connection, but one can have internet and normal stuff.