• Some naturally-occurring optical illusions require standing at a particular angle or visiting at a certain time to work.
  • Others are just tired cliches, like taking a photo appearing to hold up the Leaning Tower of Pisa in Italy.
  • These 14 photos show that expectations don’t always match reality.
  • Visit Insider’s homepage for more stories.

Real-life optical illusions can present unbelievable views when the conditions are just right. But some phenomena remain invisible unless they’re experienced from particular angles or at certain times of the year.

These 14 photos of optical illusions from around the world show that expectations may not always match reality.

Sand dunes in the distance at Deadvlei, a white clay pan in Namibia, look like a painted backdrop from a low vantage point.

Foto: Dead camelthorn trees at sunrise in Deadvlei, Namib-Naukluft National Park, Namibia. Source: Anna Morgan/Shutterstock

When the sun hits sand dunes on the clay pan inside Namib-Naukluft National Park in Namibia, the dried remains of camel thorn trees look like they’re part of a painting.

But when the lighting and angle aren’t exactly right, it just looks like an arid landscape.

Foto: Dead camel thorn trees in the clay pan of Deadvlei. Source: Wolfgang Kaehler/LightRocket via Getty Images

It’s a scenic desert backdrop, but not an optical illusion.

A rock formation known simply as "The Wave" in Arizona plays with depth perception and appears to almost be in motion.

Foto: "The Wave" in Arizona. Source: Suttipun Sungsuwan/Shutterstock

Due to high demand and the area's fragility, visiting the site requires a permit distributed through a lottery system.

The waves aren't as defined in all parts of the rock formation as one might expect.

Foto: Hikers amongst the unique troughts of "The Wave" rock formation. Source: MARK RALSTON/AFP via Getty Images

Only 20 people are allowed to visit the site per day.

The reflection in the water under Rakotzbrücke Bridge in Germany forms the illusion of a perfect circle.

Foto: Rakotzbrücke Bridge. Source: Lukasz Stefansk/Shutterstock

Built in 1860, it was known among locals as "Devil's Bridge," because the bridge appeared to be so miraculous that it must have been built by Satan.

But when looking at the bridge from the side, the optical illusion isn't visible.

Foto: Rakotzbrücke Bridge from the side. Source: Westend61/Getty Images

It just looks like any other bridge over a body of water.

Uyuni Salt Flat in Bolivia is the world's largest salt flat. The expansive surface is perfect for creating optical illusions that play with perspective.

Foto: An optical illusion photographed in Bolivia. Source: iFerol/Shutterstock

Tourists often place toys, packages of food, or other everyday objects in the foreground and photograph themselves further away to appear dwarfed by them.

The salt flat is also one of the world's largest sources of lithium, with an active lithium plant on site.

Foto: A bulldozer is seen at the lithium plant on the salt flats of Uyuni, Bolivia. Source: David Mercado/Reuters

The salt flats contain about 15% of the world's lithium, according to the US Geological Survey. Bulldozers and piles of salt can get in the way of the empty horizon used to create optical illusions.

Most tourists who visit the Leaning Tower of Pisa in Italy take a photo pretending to hold up the tower.

Foto: At the Leaning Tower of Pisa. Source: SolStock/Getty

The tower leans at approximately 3.99 degrees.

From a closer angle, the crowds of people all holding their arms out look a bit silly.

Foto: They're all taking the same photo. Source: Shutterstock

It's one of the most cliche travel photos that tourists can't seem to stop taking.

Every year, Horsetail Fall in Yosemite looks like it's on fire around the second week of February.

Foto: Horsetail Fall. Source: Phil Hawkins/Reuters

When the sun hits the water at just the right angle, the water looks like glowing red and orange lava.

If you visit any other time of year, Horsetail Fall is a regular waterfall.

Foto: Horsetail Fall without special effects courtesy of the sun. Source: Anastassiya Bornstein/Shutterstock

Without the sun's special effects, there's no optical illusion.

There appears to be an underwater waterfall off the shore of Mauritius in the Indian Ocean.

Foto: Mauritius. Source: Myroslava Bozhko/Shutterstock

It's actually sand getting pushed off an underwater shelf called the Mascarene Plateau.

But the optical illusion isn't visible from the shore.

Foto: A beach on Mauritius. Source: leoks/Shutterstock

Enjoying the Mascarene Plateau requires an aerial view.