Story highlights The wall must be impossible to climb without a ladder and resist attempts to penetrate through or under it

Bidders have about two weeks to develop and submit their plans

Washington (CNN) It should be tall, climb-resistant, difficult to penetrate and blend into the landscape.

Those are among the requirements for the US-Mexico border wall released by the federal government late Friday, kicking off a bidding process that will lead to one of the largest government construction projects in US history.

"The wall design shall be physically imposing in height," Customs and Border Protection outlined in the notice for contractors. That means 30 feet tall, although the officials wrote that "designs with heights of at least 18 feet may be acceptable."

The wall must also be impossible to climb without a ladder, and should make it difficult to use "common and more sophisticated climbing aids," like grappling hooks.

In addition, the wall must resist attempts to penetrate through or under it. The request specifically mentions it must successfully endure for at least 30 minutes -- but ideally more than four hours -- attempts to bore through it with a "sledgehammer, car jack, pick axe, chisel, battery operated impact tools, battery operated cutting tools, Oxy/acetylene torch or other similar hand-held tools."

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