How do we know precisely the locations of the geographic poles? And how did we know our location relative to them before GPS?

Question

Basically, how can we measure the Earth’s rotational axis accurately enough to be able to erect a physical [pole](https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fantarctic-logistics.com%2Fwp-content%2Fuploads%2F2016%2F08%2Fdestination-south-pole-1.jpg&f=1&nofb=1) that goes through it? And how did expeditions in the early 20th century know when they successfully reached the poles?

In: Other

Answer 1

From the best I can find it is a mixture of using nautical and aerial charts and a sextant to accurately measure the Latitude and Longitude using celestial observation. The navigation was verified later by looking at the recorded sextant data and checking it with charts. The first verified successful attempt for the north pole was in 1926 by aircraft.