Story highlights The campaign raised more than $26,000

The photos are of stray cats from two shelters

(CNN) If your dog travels with you, it might be better to avoid Clapham Common Tube station for the next couple of weeks.

The London subway station is overrun with cats.

They are everywhere -- staring at you with their steely cat eyes from giant posters on the wall and from stick-ons on turnstiles.

It's part of a crowdfunded campaign to replace all ads with pictures of kitties.

A black cat watches through barriers

The campaign, which began Monday, raised more than £20,000 ($26,000) to make 68 ads at the station disappear. In their place are photos of stray cats from two rescue groups, Battersea Dogs & Cats Home and Cats Protection.

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