By the late 1800s sailing routes to the continent were well known and a number of people had landed on the island. Shortly after this, a race to the south pole began. The two primary contenders were Roald Amundsen, a Norwegian and Robert Scott, a Brit. The two arrived to the pole within weeks of each other, but Amundsen reached the pole first, as Scott and much of his expedition died on their return from the pole.
By the 1950s a number of countries were setting up stations on Antarctica, primarily used as research bases. The United States set up a station at the south pole, called the Amundsen-Scott South Pole Station in honor of the poles first two expedition leaders and this station remains in use to this day.
On December 1, 1959 the Antarctic Treaty was signed, which does a number of things, most importantly it restricts all military activity on the continent and encourages scientific research. Today there are a large number of countries with research stations on the island, some of which are permanent and others which are temporary or seasonal.