The brightest spot on the Moon is a crater called Aristarchus. It's bright enough that people have mistaken it for activity on the surface.

Aristarchus sits on a plateau of unusually reflective material and is geologically fresh, making it stand out sharply even in binoculars. It's also the most reported site of transient lunar phenomena: brief glows and hazes that observers have logged for centuries and nobody has satisfactorily explained.