Ever watch "Star Wars" or "The Fifth Element" and wonder when we'll see droids, cars or podracers zooming around between skyscrapers? Amazon just came one step closer to making those futuristic worlds a reality.

The U.S. Patent and Trademark Office on Thursday published a 2015 patent filed by the online retail behemoth for multi-level fulfillment centers that would serve as urban hubs for armies of delivery drones.

Drawings in the application depict towers roughly six stories tall peppered with windows to allow drones to easily enter and exit the building. Packages would likely come in at the ground floor, by truck, rail, ship or perhaps by air.

Robots - including "elevator robots" - would move the packages to the appropriate level for drone pickup. The drones may also have wheels to use within the center. The hives would be populated with both robots and humans to service the drones when needed.

This is a cross-section of one of the hives.

The drone hubs could process hundreds or thousands of orders each day, the application says.

The fulfillment centers could also serve as a pickup location for customers, and could include lockers for temporary package storage.

In the patent application, Amazon says traditional fulfillment centers on the outskirts of large cities - like the one planned for a Troutdale industrial park - aren't cutting it anymore.

"These locations are not convenience [sic] for deliveries into cities where an ever-increasing number of people live," it says.

Some of the designs for the fulfillment centers look pretty out-there.

Building fulfillment centers that mimic high-rises in city centers will enable Amazon to deliver items to city-dwellers more quickly.

Though it's unclear whether Amazon will move forward with its ambitious plan, the publication of the patent comes on the heels of the news that Amazon plans to buy Whole Foods, and that it plans to roll out a clothing delivery program akin to the popular Stitch Fix service.

Downtown high-rises full of delivery drones could potentially get groceries and clothing to Amazon's customers more quickly.

Amazon unveiled its drone delivery program in 2013, and made its first drone delivery in December in the U.K. The company also received patent approval for blimps that would float above cities and serve as drone hubs.

-- Anna Marum

amarum@oregonian.com

503-294-5911

@annamarum