Uphill in a downhill
At kilometer 11,600 of the road that connects Ariccia, Rocca di Papa and Grottaferrata, nearby Rome, there is an unusual phenomenon where it seems that the gravitational field is reversed.
The street appears to be uphill, but, when you place an item on the ground, instead of descending, it climbs up, even the cars do so.
The phenomenon has been studied using different methods, including an analysis of the magnetic fields considering the volcanic origin of the area. In the end, scientific studies have shown that it is an optical effect: what seems to be an uphill, is instead a downhill, the famous “Uphill in a downhill”.