21 Fascinating Pictures You've Probably Never Seen Before

1.

Five pounds of fat compared to five pounds of muscle

2.

A 3D-printed face

3.

A cross-section of an undersea cable

4.

Octopus eggs

5.

A geyser just before eruption

6.

A look inside one of Google's data centers

7.

A microscopic image of a human tongue

8.

A rare 360 degree rainbow captured from an airplane

9.

A tree frog wearing a lizard as a hat

10.

The clearest photo of Mercury ever taken

11.

An aerial view of a scrap tire dump

12.

Cancer cells under an electron microscope

13.

Einstein's desk hours after his death

14.

George Washington's Teeth

15.

Mars in true color from the Curiosity Rover

16.

The inside of a burning log

17.

The inside of a FedEx Boeing 757 without any cargo inside

18.

The Northern Lights from space

19.

What pugs looked like before selective breeding

20.

Where the Great Wall of China ends

21.

X-rays before and after treatment for scoliosis