These are some of Earth's best underground attractions that are hidden in the shadows beneath the surface.

Here MailOnline Travel compiles the best of the best including an eerie world of underground living in Australia to neon trampolines and slides in Wales. 

The catacombs contain the skeletal remains of more than six million people whose bones were relocated here between 1785 and 1860, when the city's cemeteries became full.

You would have to look closely for one of its obscure entrances in the French capital of Paris, but should you stumble upon one, it reveals an underground world of the dark, dank, narrow tunnels with a fascinating history.

Below the City of Light's 12million residents lie the remains of millions before them.

The Paris catacombs are a 200-mile network of old caves, tunnels and quarries - and much of it is filled with the skulls and bones of the dead.

While most visitors tour the catacombs by day, two brave tourists were able to stay the night at an Airbnb macabre mastersuite for free this Halloween. 

The evening consisted of a private tour of the labyrinth of bones and skulls, a daunting culinary experience to the sound of violins and a bedtime storyteller who will read some catacombs legends before the pair sleep alongside the remains of Jean de la Fontaine, Charles Perrault and François Rabelais. 

(dailymail.co.uk)