Even 9 lives can't withstand 20 degrees below zero -- which is why Chicagoans are on a mission to save hundreds of thousands of stray cats ... with the help of tons of straw.

A grassroots community in Chi-Town called "Chicago Community Cats" has been bracing for a week for the polar vortex temperatures by prepping makeshift shelters for stray and feral cats. Erica Roewade, who runs the group, says about 200 people have been working around the clock to build straw-stuffed bins to keep the kitties warm.

It's a huge undertaking. Chi-Town reportedly has roughly 200k feral cats roaming its streets and alleys.

Roewade says the group has also purchased about 100 "Snuggle Safe Disks" (which also keep pets warm), heated water bowls and other supplies to distribute throughout the city.