Located in East Sussex, England; the Hellingly Hospital is an abandoned Insane Asylum. It was opened in 1903 and was known to perform lobotomies and electrocuted their patients. They were finally shut down and it has since then been abandoned since 1994. It is said to have a lot of paranormal activity from screaming, apparitions shadows and more. It’s very popular among the ghost hunting community.
Here is where you can read more about it and find photos.