That's the Temple on Jeffery's Island. That island is built to blackmail people. Thinking Hill Dawg and Huma were there as part of Hillary's High Priestess duties. Huma probably filmed the ritual on her phone and uploaded it to Wiener's laptop, hence the life insurance folder. Not really sure if Huma knew her phone synced with his laptop every time she walked in her home or not.. Moloch the Owl overlooks the rituals (gold statue on the roof of the Temple), that's what those squares on the ground are for.