It was a dump, but now it's pretty.

A clearing in the South Valley bosque is covered with shards of glass from old soda bottles and medicine jars, glinting through the weeds.

This is what remains of Albuquerque's first municipal dump, which was probably used from the 1930s until the end of World War II.

"When the sun is shining on it just right, it looks like a river of glass," said Mary Holyoke, who has visited the dump several times. "It's absolutely beautiful."

Before the '30s, there was no organized trash collection in the city, and most people buried their trash in alleys or fields, said Matt Schmader, Albuquerque's superintendent of open space.

The dump also has discarded metal cans and broken slabs of concrete.

Albuquerque's early residents dumped everything else there, too, but burned the trash regularly. What's left are the things that survived the fires and time, said Ed Boles, historic preservation planner for Albuquerque.

Schmader said the dump poses no known environmental threat. The glass and concrete are safe, and anything that was in the bottles has decomposed, he said.

Many of the bottles — some of them warped, probably from the trash fires — bear markings distinctive of the dump's era.

Several pint liquor flasks found at the dump have "Federal law prohibits sale or reuse of this bottle" embossed across the top, a marking meant to discourage bootleggers after Prohibition was repealed in 1933.

The dump is a little-known historical treasure, Schmader said, and he wants to keep it that way. He discouraged The Tribune from publishing a map or directions to the dump.

But some people stumble across the dump, or hear about it.

Jon Knudsen, a blogger and retired teacher, said he has visited the dump three or four times.

He heard about it 20 years ago from a friend.

"He told me these stories that as a kid, he would wander around this valley of glass," Knudsen said.

His friend could not remember where it was, and Knudsen forgot about it until he came across it on a bike ride a few years ago.

Knudsen said he's never taken anything from the dump.

Instead, he photographs or memorizes details of the bottles, and dates them using Bureau of Land Management and Clorox Web sites.

Most of the valuable artifacts have already been taken from the surface of the dump, leaving only broken or common pieces, Schmader said.

Boles said he suspects that some scavengers dig into the piles to find more intact and valuable pieces.

"It's so big, I think it would take a lot of scavengers to really do any damage," he said. "It's still something I'd rather not risk."

Jay Hart, Albuquerque's director of Parks and Recreation, said penalties for removing property from the dump can include a $300 fine and 90 days in jail.

Liza Wheeler, an Albuquerque writer who was shown the dump by Holyoke, said she visits the dump for its aesthetics rather than its history.

When Wheeler's brother came to town, she skipped the museums and took him to the glass dump.

"He definitely appreciated it for the crazy little spot that it was," Wheeler said.