The modern marimba has a range of five octaves - that's 61 bars made out of Honduras Rosewood. As you can see in the picture, the bars of the marimba are layed out in the same pattern as a piano keyboard, with "black" keys and "white" keys. Under each of the bars is a cylindrical resonator which dramatically amplifies the sound of the bar.

The marimbist plays the instrument using mallets. There are many different kinds of mallets (as you can see in the photo). The marimbist plays with four mallets simultaneously, holding two in each hand.