Lollapalooza opened its gates Thursday, set on bringing some of the biggest music artists to Chicago's Grant Park across four days. But before you head over, you'll need to know what's allowed inside.

While backpacks and bags with multiple pockets are prohibited, small purses, totes and drawstring bags will be allowed on festival grounds. All bags will be searched before entry.

Bags exceeding 12” x 12” x 6" in size will not be permitted, and all bags must be clear and made out of plastic, vinyl or pvc. Small clutch purses and fanny packs that are  4.5” x 5.5” or smaller don't need to be clear, but can have no more than one pocket.

Hydration packs are allowed and don't need to be clear, but must be empty and have no more than two pockets in addition to the one holding the water reservoir.

A number of items will not be allowed in the venue this year. Here's a look at what is and isn't prohibited:

The following items are allowed:

The following items are prohibited: