What type of navigation aid is permanently attached to the earth's surface?

A beacon is a navigation aid that is permanently attached to the earth's surface, typically situated on land but also found on fixed structures in the water, such as piers or jetties. Beacons are designed to emit light, sound, or other signals to assist mariners in determining their position and navigating safely.

Buoys, on the other hand, are not fixed to the bottom and can float freely on the water, marking channels, hazards, or providing information to navigators. Floating lights are also not permanently affixed, as they float on the water and can move with the tides and waves. Markers may refer to various types of navigation aids, but they often include both fixed and floating types and do not specifically denote a structure that is permanently attached to the earth's surface. This distinction solidifies why a beacon is the appropriate answer for this question.