The idea to use neutrinos as cosmic messengers dates back to the 1950s,
and the concept of Cherenkov Neutrino Telescopes deep underwater to the
year 1960. It took more than half a century before a detector large
enough to detect cosmic high-energy neutrinos was built: The IceCube
Neutrino Telescope at the South Pole. I will decribe the way towards
IceCube construction and sketch IceCube's main results, starting with
the discovery of a diffuse flux of cosmic neutrinos in 2013. I will also
try a look into the near future, where IceCube will be flanked by
telescopes of similar size in the Mediterranean Sea (KM3NeT) and in Lake
Baikal.
