This may come as a surprise to the Public Utilities Department, but according to Dean Hutcheon there are crocodiles under State Street. And train tracks under there, too, says Astyn Shaw. Also gold.

When first grade teacher Barbara Andrade asked her students at Nibley Park Elementary to list what you might find under Salt Lake's streets, the answers revealed how mysterious things are when you can't see them.And how ignored. Except for occasional forays into our basements, most of us in Utah spend our days above ground, giving little thought to the complex and efficient network of pipes, cables and tunnels right under our feet.

If you could peel the asphalt off the intersection of State Street and 100 South, for example, you'd find - no matter how quiet it is at street level - that this is the busiest corner in the city, says Chris Meeker, engineering records manager in the city Public Works Department.

While we wait impatiently for the traffic light to change, the life blood of the city is passing underneath - natural gas, drinking water, electricity, melting snow, sewage, fiber optic cables and the timer that will eventually change the light from red to green.

Just a few blocks to the west, from 300 West to about 1200 West, and 1300 South to 700 North, the streets also hide something else: Garbage. Or, if you prefer, artifacts.

According to Duane Fuller, superintendent of streets and sanitation for Salt Lake City, the pioneers used trash as landfill to build up swampy areas on the west side. Layers of garbage would be alternated with layers of dirt, and eventually, says Fuller, the streets were so high you could sit on your porch and be eye-level with the road. In some places, he says, the garbage was eight feet deep.

When his road crews began excavating the roads in the early 1970s to bring them down to an acceptable level for storm drainage, they found old dishes, pots and pans, bottles and even a pair of cowboy spurs.

Like the first graders at Nibley Park, adults sometimes have some strange notions about Salt Lake's underground. There is, for example, the legend of the tunnel between the Salt Lake Temple and the Great Salt Lake. Rumor has it that this engineering marvel was used to spirit away polygamous wives.

A lot of cities have tunnel legends, says Barre Toelken, director of Utah State University's folklore program. Usually, he says, the tunnels harbor some sort of secret or nefarious activity. In Price, for example, legend has it that there was a tunnel between city hall and a local bordello.

In Salt Lake there are a few real tunnels, but all of them are pretty mundane. There is a tunnel, for example, between the Church Office Building and the Salt Lake Temple, and another one under 200 East, between the City and County Building and the Metropolitan Hall of Justice. When there were still courtrooms in the City and County building, prisoners were transported through this tunnel, but the tunnel's main function has always been to transport steam.

There are also steam tunnels under Main Street. Dug by hand in 1910 by the Hotel Utah, the tunnels are now operated by Utah Power and Light from the steam plant at 40 N. 200 West.

It's about 105 degrees down in these tunnels, guesses plant superintendent Lyle Heaps as he leads the way between two lengths of pipe that stretch as far as the eye can see. Steam in the high pressure pipe travels along at a temperature of about 350 degrees, he says.

The tunnel also houses fiberoptic cables for KSL and a security system cable for Temple Square. Back in 1968, says Heaps, when President Lyndon Johnson came to town, the FBI checked the steam tunnels to make sure no hippies or other malcontents were planning any underground activity underground.

Utah Power and Light's domain also includes hundreds of miles of electric wires, fed through conduits under downtown streets. At various points under the streets the wires converge in transformer vaults and switching vaults. Located about 20 feet under the traffic, these vaults are as big as rooms and are entered through manholes. Other manholes lead down to narrower vaults lined on the bottom with several inches of mud.

"Do you know why manholes are round?" asks John Serfustini, director of editorial services for Utah Power and Light and an expert on such things. "It's the only geometric shape that won't slip into its own hole."

The manhole covers are pretty heavy, but that hasn't stopped at least one transient from spending a dry night down among the cables. These are accommodations not without a certain amount of risk: Down some manholes, noxious fumes such as methane accumulate and can be deadly if the hole isn't ventilated well first.

Salt Lake's streets also house underground canals, some of them as big as 6 by 10 feet, that carry water from local canyons down through the city. One of these, the Jordan-Salt Lake canal, was originally built to float granite blocks from Little Cottonwood Canyon to the Salt Lake Temple, although it was never actually used for this purpose, according to Charles H. Call Jr., a drainage engineer for Salt Lake City Public Works.

U.S. West operates thousands of miles of telephone cables under city streets. AT&T has just completed miles of fiberoptic cable containing pairs of hair-thin strands of glass that can carry more than 24,000 telephone conversations at once. Mountain Fuel maintains 4,400 miles of underground natural gas lines.

And of course there are sewers, 778 miles of them, some of them 19 feet under the street. But, and this might surprise the kids in Mrs. Andrade's class, there are hardly any rats in Salt Lake's sewers. And there are no crocodiles at all.