Sign of the Apocalypse of the Day:

Wal-Mart Stores Inc. plans to open more than 1,500 stores in the United States in the coming years, on top of nearly 3,200 it already operates, the world's largest retailer said Tuesday.

John Menzer, the company's vice chairman and head of its domestic Wal-Mart stores division, said Wal-Mart was on schedule to meet an announced target of between 335 and 370 new U.S. store openings this year after 341 last year.

As part of its growth plans, Wal-Mart also is experimenting with new formats for Supercenters to fit the big box structures into tighter urban neighborhoods. New styles will include multilevel stores and underground or above-store parking rather than a huge lot out front.