PPF/New York Dresden files
During the liberty island heydays when immigrant traffic was at its peak, the border between nevernever & the mortal world started the become thinner than ever before. So thin was the border that some major powers pulled & stabilized the problem beneath the island into Lower Liberty beneath the island. Lower Liberty itself is a place where the mortal world & nevernever are merged & intertwined as one bellow ground all the way to the UN headquarters.
Lower liberty is not a safe place by any stretch given a lack of actual authority interested in keeping it safe for mortals. Any interactions there should be done with extreme caution given that the most innocuous looking individuals there can be off the chart powerful beings, Kuru being the only one of them yet encountered.