Sanibel beaches attract visitors from all around the world, partly because of the large quantities of seashells that frequently wash up there. Many sand dollars can be found as well. One of the reasons for these large accumulations of shells is the fact that Sanibel is a barrier island which is "part of a large plateau that extends out into the Gulf of Mexico for miles. It is this plateau that acts like a shelf for seashells to gather." Sanibel also has an "east-west orientation when most islands are north-south. Hence, the island is gifted with great sandy beaches and an abundance of shells."