This is definitely one of the more unusual postcards I've ever received from New Zealand!
Napier Prison is a former prison in Napier that was New Zealand's oldest prison. It closed in 1993 and is now an historic facility which offers guided tours twice daily and self-guided audio tours all-day, and also offers accommodation for backpackers. It is also the only building where it is possible to see the original path of the 1931 Hawke's Bay earthquake.
Napier Prison was constructed on Napier Hill in 1862 and was used until the early 1990s, being officially decommissioned in 1993. In addition to being a prison, the location was also used as an orphanage and a psychiatric unit. During the 19th century, five hangings were conducted at the prison.
There have been many reports of ghostly occurrences at the site such as unexplained footsteps,disembodied faces, doors opening and closing on their own, and the ghost of a murderer on the anniversary of his execution. The best known former prisoner is Roland Edwards, a mass murderer who reputedly has his spirit haunt the area. In 2011, a team from the television series Ghost Hunters International spent four days at the old prison and "were not disappointed".
I quite like the stamp in the bottom left corner - my middle name happens to be Elina! :D