When it comes to private art collections, the huge holdings of Roman Abramovich, Steven A. Cohen, and Eli Broad have nothing on Carlos Slim, the world’s richest man. A self-made tycoon, Slim, the son of a Lebanese immigrant, made his fortune in the Mexican telecom industry. With a cache of some 66,000 pieces, including works by El Greco, Matisse, Monet, and van Gogh, this month he opens a spectacular new museum in Mexico City to display them.

Designed by Slim’s 38-year old son-in-law, Fernando Romero, the six-floor, 183,000 square-foot Soumaya Museum in the city’s Polanco district is shaped like a wonky futuristic hourglass layered with aluminum hexagons. And it is far from being merely a nepotistic vanity project: Romero formerly worked with Rem Koolhaas’s OMA and was the winner of the Mexican Society of Architects’ inaugural Young Architecture Award in 2009.

The new Soumaya, named after Slim’s late wife (it also means “little heaven” in Arabic), will throw open its doors this Wednesday with a private party, followed by a series of banner exhibits in the new year. The first floor will feature Slim’s Auguste Rodin collection—the second largest outside of France; other galleries will showcase rare Mexican gold coins, pre-Columbian art, and works from Mexican painters Diego Rivera and Juan Soriano. “The museum will give us an opportunity to look at the vision of a man who isn’t just interested in one thing,” says the museum’s director, Alfonso Miranda Márquez. “It’s a collection of collections.”

This architectural landmark will no doubt strengthen Mexico City’s already formidable credentials as a cultural destination. Better still, it seems Slim’s philanthropic passions have infected other members of Mexico’s super elite—just next door to the Soumaya, Jumex juice heir Eugenio Lopez is in the process of building his own contemporary art museum designed by the illustrious David Chipperfield.

Little heaven? Large ambition may ensure it.