Why is mercury called the forgotten planet?

Mercury can claim the title for the “weirdest” planet in the solar system, apart from being the smallest and the innermost. It has the wildest temperature extremes – from 800’c to to 300’c and drifts from being the nearest to being the farthest from the sun. Reaching mercury poses significant challenges as the planet orbits close to the sun. Hence, it is regarded as the forgotten planet in the solar system.