There are more than 150 caves found in the Rock of Gibraltar, but only one gets to take home the ‘most-visited’ prize. St. Michael’s Cave gets that honour, in no small part because of its awe-inspiring collection of stalactites and stalagmites. All of the formations are lit up in a variety of vibrant colours in order to accentuate the majesty of it all, creating magnificent photo opportunities for more than a million visitors every year. The cave was initially supposed to be an emergency hospital during World War II but never functioned as one, instead developing naturally into the wonder we see today. The splendid acoustics aren’t wasted either, with the occasional concert or gig held in this stunning spot.