Lightning near the North Pole reveals dramatic climate changes as Arctic temperatures rise and storms intensify.

Reaching the North Pole was an international obsession ... Nobody had figured out a good way to steer them yet. Once a balloon was up in the air, it was at the mercy of the wind and simply drifted.

Andrée was one of the most famous Norwegian explorers of the late 1800s. In 1897, he set off on an expedition to the north ...

This storm began over the Arctic ice sheet, moved toward the North Pole, crossed the Greenwich Meridian ... where a stream of warm, moist air was pushed northward over the ice cap.