The ‘Strange Slope’ optical illusion in China where uphill looks like downhill

Yes, your eyes are deceiving you. This slope looks like it’s going downhill when, actually, it’s going uphill, and uphill when it’s actually going downhill.

Known as ‘Strange Slope’, it lies 30km (18.6 miles) northeast of the city of Shenyang in China’s Liaoning Province. The strange optical illusion that the slope creates was discovered in 1990, and it has been drawing crowds of tourists to the area ever since. 

Videos recorded by those who visit the slope demonstrate the phenomenon in footage that sees cyclists slowly peddling along what appears to be a downhill direction, then turning around and seemingly freewheeling uphill. 

The ‘Strange Slope’ optical illusion in China’s Liaoning Province (pictured) where uphill looks downhill and downhill looks uphill 

The slope, measuring 262ft (80m) long and 49ft (15m) wide and also known as the ‘Spooky Slope’, has two tracks – one inner track for cyclists to test out the bizarre optical illusion, and a second outer track for cars.

One Tripadvisor reviewer wrote: ‘This slope is weird… it is very fast when going “uphill”, and it is very laborious when going “downhill”. It doesn’t matter whether you are riding a bicycle, walking or driving, it is the same.’

A second described it as a ‘peculiar phenomenon’, adding: ‘When riding a bicycle “down” the slope, you had to pedal hard, but it was very easy to go “uphill”.’

‘Strange Slope’ is around 30 minutes by bus from the city of Shenyang 

And a third simply branded it a ‘very strange place’.

So what’s causing the illusion?

Jose Sasian, professor of optical sciences and astronomy at the James C. Wyant College of Optical Sciences at the University of Arizona, believes that the effect is created by the building in the background appearing to be seen from above.

‘The near vanishing point also contributes to the illusion,’ he added.

The area that surrounds the attraction is known as the ‘Strange Slope Scenic Area’, with the slope one of ‘three mysteries’ in the area, according to Travel China Guide.  

The other two are the nearby hills of Xiangshan and Wongding. When a person stomps on these hillsides, they’re said to hear sound boom from the earth below.

The nearby forest-covered mountains of Yunmao, Wolong, Guibei, Changkong and Dagu, known as the ‘Five Great Mountains’, also attract day-trippers. There’s also a ski resort in the vicinity, Guaipo International Ski Resort, with slopes suitable for both beginners and experienced skiers. 

Strange Slope is around a seven-hour drive from Beijing and 30 minutes by bus from the city of Shenyang. 

Guided tours of the area are available, with entry to Strange Slope costing £4.80 (40CNY).