If Princess Peach's luxurious castle from Super Mario 64 actually existed, Natalie Grigson of real estate-focused blog Movoto estimates that it would be worth approximately $950,972,940.
The price is based off several factors, including the square feet and assumed location. Grigson estimates that the castle's front double doors are about 72-inches wide; using this calculation, the castle would be approximately 453,060 square feet, or roughly the size of Harry Potter's school, Hogwarts.
As for the castle's location, Grigson puts it in Oslo, Norway, thanks to surrounding grassy fields, mountains, waterfalls and plant life. Judging by the price per square feet of homes in the area, that makes each square foot worth about $2,099.
Grigson adds that the grand total does not include the property the castle is on, the moat or any of the interior items. You can read more about how the price was calculated over at Movoto.