MEXICO CITY  At their best, museums are glorious cultural repositories, reflecting the highest flowering of human creativity, ingenuity and art. But not everything in every culture is glorious, and there are museums for those aspects, too, which is why, hidden from the public, there is an institution here devoted to Mexico’s dark side, the Museum of Drugs.

It is a place that leaves those who manage to get inside shaking their heads and lamenting the long, spirited but largely unsuccessful war this country has waged to control illegal narcotics.

Run by the Mexican military and open only to graduating cadets and select guests, the Museo de los Enervantes presents the drug war in all its ugliness and complexity. There is a room devoted to the ancient roots of drug use in Mesoamerica, like the use of hallucinogenic peyote and mushrooms by the Maya and Aztecs, and displays that show all the military does to try to stem the tide, uprooting marijuana plants and uncovering hidden caches of cocaine and heroin.

“You eradicate in one place and you continue on, and when you go back they’re growing it again,” said Maj. Mario Ayala López, who insisted that his face not be shown in any photographs, an atypical request for a museum curator but a reality in present-day Mexico, where the drug violence knows no bounds.