Beginning with next week’s Supergirl, The CW will commence with its four-night crossover event featuring the Kryptonian strongman (Melissa Benoist), Green Arrow (Stephen Amell), The Flash (Grant Gustin), the Legends of Tomorrow, and characters in between. We’ve already seen the Dominators, the aliens who’ll be invading Earth, but there might be another surprise guest: the famous Justice League headquarters, the Hall of Justice.

The location could just be a fun background for the four new posters released for the crossover event and nothing more. The CW has a habit of tapping into comic book imagery to make compelling poster art, but it’s still fun to see the home base looming large behind our heroes. Also spotted in the posters are Martian Manhunter, Cisco, Diggle, Felicity, White Canary, The Atom, Firestorm, Heatwave, and a member of the Dominators.

Based on the official episode descriptions, we know that Barry and Cisco travel to Kara’s Earth at the end of Monday’s Supergirl to ask for her help in battling an alien invasion. The following episode of The Flash will see the Dominators attack Central City, which brings Team Arrow and the Legends into the picture. Arrow will bring an alternate reality to Oliver Queen — one where he never became the masked vigilante — before the final showdown occurs in Legends.

The CW also released a found-footage-esque clip from Legends, featuring a “classified” military recording of a American soldiers battling the Dominators in the past. They don’t stand a chance against the aliens’ high-tech weaponry. Watch it below.

Elsewhere, you can pour over the 50-plus images from the four-episode story arc and multiple trailers before the action commences beginning this Monday, November 28th, at 8 p.m. EST with Supergirl. The Flash will follow on Tuesday, November 29th and then Arrow on Wednesday, November 30th, and Legends of Tomorrow on Thursday, December 1st.

See all four posters below.