The world is a fairly mind-boggling place. There is so much going on that only makes sense to us humans because we're used to it, and so much more that goes beyond our understanding and bedazzles, bemuses and fascinates us every day.
Often, our planet throws up a dazzling show for us in the shape of natural illusions, works of natural art which require a second look and a double take to catch their majesty. Spread across the globe, these crazy-but-true tricks of the light are incredible to see and we've compiled a handy list right here for your delectation:
Underwater Waterfall, Mauritius
Out in the Indian Ocean, located off the shore of Madagascar, the picture-perfect white sands of Mauritius lie, quietly minding their own business in an idyllic paradise. But if you head down to the south-west corner of the island, you'll stumble across one of the most striking maritime illusions in existence: a spectacular underwater waterfall, crashing over the side of an ocean shelf to the navy depths below. Obviously this isn't a matter of 'heavy' water cascading over the 'lighter water. Rather, it can be explained by the sands of neighbouring beaches which are dragged down into the 4,000-metre-deep abyss by a series of monumental ocean currents.
Whatever the explanation, this sight is a glorious one best seen from above by plane or even by boat. It is magnificent, and the image of the crisper, turquoise currents being dragged into the deeper blue of the ocean is one not to be forgotten.
Salt Flats, Bolivia
Are you walking on water? Have you made it to heaven? Have you arrived on another planet? All reasonable questions for those who find themselves on the incredible salt flats of Bolivia, known as the Uyuni Salt Flat.
The largest of its kind in the world, stretching off into an infinity of white, these regions are made up of miles and miles of completely flat salt fields. The crisp white of the salt, combined with the pure blue of the sky lend this part of the world a surreal feeling of nothingness, a sensation of having stumbled outside of life's comic panel and into the white of the paper beyond. The rainy season changes this by transforming the ground into an endless mirror image of the sky. Both scenes can bring out different reactions from different people: it can cast a spell of wonderful tranquillity and solitude, inspiring reflection and introspection, or it can deeply unnerve and unsettle, giving an impression of the enormity of existence.
Whatever your reaction, the Bolivian Uyuni Salt Flat is a sight well worth seeing in all of its glory and can be found in the south-west of this South American nation.
Blood Falls, Antarctica
Let's head even further south now, across the ocean down to Antarctica where it looks like a murder has happened.
On the eastern seaboard of the southern ice continent, gallons of thundering scarlett water plummet over the side of a cliff onto a lake below. Thanks to their sanguine colour, this disturbing-looking phenomenon has earned the ominous moniker the Blood Falls, and understandably so. It almost looks as though someone or something has been slaughtered upstream, with its blood mingling with the water to fuel the waterfall. It's dramatic, eye-catching and an impressive installation to see.
It was originally thought that the grisly streaks of red were caused by algae affecting the colour. But as recently as 2017, scientists have discovered that it is actually oxidising iron in the saltwater which gives the falls their vivid hue. Essentially, it's just an innocent waterfall of rusty water.
The Vermillion Cliffs, USA
In the heart of the remarkably beautiful state of Arizona in the southern part of the USA, there lies a smorgasbord of incredibly rock formations, carved in all manner of bizarre shapes and forms. Towering boulders teetering on spindly legs, structures which would look more at home on the barrier reef - anything goes in Arizona as far as nature goes.
But we're going to pick out one which stands out - the sublime Vermillion Cliffs. Thanks to years and years of eroding and grinding down, nature yields its completed masterpiece: a set of 'steps' on the Grand Staircase of the Colorado Plateau. The jewel in the crown of these cliffs is the fantastic Wave, a sandstone formation in the shape of sweeping, undulating curves and layered rock. It looks almost like liquid, and when the rains come and puddles form, the Wave casts an even more enchanting sight as the layers are reflected in the water.
It's really something to see and the Wave is just one of Arizona's impressive natural illusions which dot its memorable natural parks and rolling landscapes.
Those are just some natural optical illusions that the world has to offer - got any suggestions? Let us know in the comments below!