Taking an observation at the pole, Roald Amundsen 1911 South Pole Expedition

One problem that arriving at the South Pole posed was determining exactly where it was. The pole itself is on a featureless icy plateau. The ice above it is moving continually but slowly. Only by very careful repeated navigational readings could Amundsen's team actually determine that they had arrived.

Thus they established that this flat white bit was the pole as opposed to that other flat white bit, they passed over half an hour ago.

Roald Amundsen - South Pole Expedition 1911

In: "The South Pole", by Roald Amundsen.

Picture courtesy NOAA