Have you ever seen a manhole cover with little glass circles in it and wondered why it was different from the others? Did you ever imagine that there were actually tunnels under the sidewalks? You'll be surprised to find out how many cities in Colorado had these tunnels. And they're still under our streets! Those manhole covers imbedded with glass circles, many that have turned purple with age, allowed light into the tunnels below. The Tunnels Under...

Un equipo de exploradores hace una expedición en un cráter en Islandia, el cual los conduce al centro de la tierra y a descubrimientos increíbles y horripilantes.

In a ruined and toxic landscape, a community exists in a giant silo underground, hundreds of stories deep. There, men and women live in a society full of regulations they believe are meant to protect them. Sheriff Holston, who has unwaveringly upheld the silos rules for years, unexpectedly breaks the greatest taboo of all: He asks to go outside.His fateful decision unleashes a drastic series of events. An unlikely candidate is appointed to replace...

"In the underground city of Caverna, the world's most skilled craftspeople toil in the darkness to create delicacies beyond compare-- wines that remove memories, cheeses that make you hallucinate, and perfumes that convince you to trust the wearer, even as he slits your throat. On the surface, the people of Caverna seem ordinary, except for one thing: their faces are as blank as untouched snow. Expressions must be learned, and only the famous Facesmiths...

"Describes armadillos and their underground homes. Simple text and labeled photos make reading easy and fun, and QR Codes in each chapter give readers access to online resources where they can learn even more."--

"Describes moles and their underground homes. Simple text and labeled photos make reading easy and fun, and QR Codes in each chapter give readers access to online resources where they can learn even more."--

A completely implausible earthquake sets Frederik Sandwich and Pernille, a mysterious stranger, on an adventure through secret and forbidden places in their small town.

"A young woman is rushed to the hospital with stabbing pains in her stomach. The chief surgeon delivers a living child with the face of an angel and the body of a tentacled monster. The doctors are unanimous that the baby must die. ... Engineer Gemma is plunged into darkness in a tunnel beneath London. Before she escapes, a strange green light illuminates a cluster of ghostly figures. Gemma is certain they were children. ... DC Jerry Pardoe and DS...

Presents a chronicle of London's underground network of rivers, labyrinths and chambers and how they have been used in various time periods, from sewers and amphitheaters to crypts and tube stations

The outer crust is under attack by the subterranean Styx who are turning ordinary humans into walking bombs and incubators for their eggs, and only Will Burrows and his band of retired commandos stand in their way--but the Styx also have problems of their own.