Mercury

Mars is essentially a large metal ball of iron with a very thin silicate crust. Mercury's core makes up about 75% of the planet. Its thin mantle is only about 300 to 400 miles thick.

If you weight 100 pounds on earth you weigh 38 here

Mars is the smallest and the densest planet.

If you could unwrap Mercury, it would be almost twice the area of Asia (44 million square km).