The Body altar is located south of the Monastery and west of the Barbarian Village.
At 7.5 experience per rune essence, it is the highest Runecrafting experience for normal rune essence, but requires a minimum Runecrafting level of 20.
The 'Temple of the Body' (as is the name given to actual runecrafting area) is a pink, organic-looking area, reflecting the "body" element of the rune. It's also shaped like a heart.
Unlike many altars, the entry point is not close to the portal though it is also quite a small area with no places to get lost.