A Total Solar Eclipse
A solar eclipse occurs when the moon passes between the Earth and the Sun, and they line up exactly. The diameter of the sun is 400 times that of the moon, but it’s also 400 times farther away. While it’s more likely you’ll be able to see a couple of total solar eclipses in your lifetime, the path of totality for each solar eclipse is different, so some locations may not experience one for centuries.
If you’re willing to travel for a solar eclipse, then you’ll have more chances of seeing one. There are at least two solar eclipses per year somewhere on Earth. From any one place, total solar eclipses are visible every 400 years. If you don’t want to leave your hometown, then hopefully you’re within these 400 years (NHM).