Mercury's days are longer than its years!

Due to the speed of its orbit, Mercury has longer days than years! It takes 88 days to complete an orbit around the Sun. A single day on Mercury is equal to two years on Mercury. It is equal to about 176 Earth days.

It is hard to see Mercury from Earth, because the Sun’s glare hides it. You can see it, however, during a solar eclipse. Two spacecrafts have been to Mercury.Source