Arthur Gebhart, age 10, of Henderson, Nev., for his question:

HOW LONG ARE THE NATURAL BRIDGES IN UTAH?

In southeastern Utah is Natural Bridges National Monument, a park that includes three natural sandstone bridges that are among the largest examples of their kind in the world. The bridges are called by their Hopi Indian names: Sipapu, Owachomo and Kachina.

Sipapu is the largest of the bridges. It is 220 feet high and 56 feet thick at the top of the arch. The arch is 37 feet wide and it spans 268 feet.

Winning second honors is Kachina bridge with a span of 186 feet and a thickness of 107 feet at its smallest part. It arches 205 feet above water.

Owachomo is the smallest and also the oldest bridge. It is only 10 feet thick in the center, but it is 108 feet high and 194 feet long.

Many prehistoric drawings appear on Kachina.

The monument was established in 1908. The national monument covers 7,779 acres of land. Camping is permitted.