"Exactly at the poles, the Sun rises one time each year and sets one time each year, at the equinoxes (around 21 March and 23 September). Tables of sunrise and sunset can be found on the Sun Position Tables Page.
Sunrise and sunset at the poles take a long time. At the poles, the Sun does not go higher and lower in the sky each 24-hour day, but goes very slowly up in the spring or down in the summer. During a 24-hour period, the Sun goes all the way around the sky at almost the same height. Around the beginning of spring, as seen from a pole, the Sun gets about 0.4 degrees higher in the sky each day. The apparent diameter of the Sun in the sky is about 0.5 degrees, so about 30 hours pass between the moment when the top of the Sun is first visible and the moment when the bottom of the Sun is first visible (assuming the horizon is level and clear in all directions), so sunrise takes about 30 hours at the pole. The same holds for sunset. During those 30 hours, the Sun moves all the way around the horizon, and then some, so if you look at the Sun for all of that time, then you'll have looked in the direction of all continents and oceans. "