Beacon

Beacons are small columns of light featured in Skyward Sword.

Uses
When Link places a beacon on his map, either on the Surface and the Sky, a blue column of light will appear, acting as his waypoint to reach the desired location. Beacons can only be placed on overworld maps by pressing the C Button.

The power to place beacons is only activated after Link first talks to the aged Impa in the Sealed Temple, at which point only one beacon can be placed at a time. Once Link reaches the northern portion of the Lanayru Desert where the entrance to the Lanayru Mining Facility is located, Fi will enable the ability to place up to five beacons on the map.