An ancient piece of corroded metal is more than it seems: an alien-looking device of intricate dials and cogs; there are over 30 gears inside and some gears have up to 65 teeth on them. Using cutting-edge imaging technology, experts examine what could actually be a 2,000-year-old computer.
How can an ancient Roman cup change colour? It's not an optical illusion. It really does change colour from red to green.

Garrett McNamara and his team return to Nazaré for another season of surfing. The team struggles through a number of accidents and challenges but eventually develop a set of safety procedures that enable them to surf Nazare's wave with less chance of injury or death. The struggles pay off when McNamara catches a nearly 80 foot tall wave that catapults him to international fame and makes him the holder of the world record for largest wave surfed.

Garrett McNamara recovers from the injuries he sustained at Mavericks and begins training to return to Nazaré for another season. While surfing at Indonesia's G-Land site, Garrett suffers more injuries that threaten to take him off the waves permanently. Meanwhile, a friend of Garretts catches an 80-foot wave at Nazaré, taking the world record from McNamara. McNamara resolves to continue his hunt for a 100-foot wave.

Edgar Davidson agrees to talk to investigators but tells a different story. Cathy’s sister Marilyn indicates her interest in solving the case. Tom Nugent casts doubt on Gerry Koob’s story about the night of Cathy’s disappearance. The search for the other man at Cathy’s apartment Pete McKeon may have information about Koob’s relationship.
What Cathy’s roommate Sister Russell knew about the abuse and Cathy’s relationship comes into question. 'Jane Doe' and 'Jane Roe' meet for the first time and talk about the Keough. Abbie investigates Baltimore’s investigation into the abuse reports they received. Marilyn Cesnik Radakovic recalls receiving a mysterious letter from her sister after her death.

A mammoth Tsunami strikes the eastern seaboard. It would be a disaster of epic proportions. Some scientists believe this catastrophe could happen one day, but how? This episode shows the Atlantic island of La Palma has collapsed several times in mega-landslides. Another could trigger a tsunami with enough power to cross the Atlantic Ocean and decimate the US East Coast.

A new video pushes panic go to the next level, galvanizing the 'internet nerds' to intensify their own painstaking investigation as police join the hunt. In the previous videos, the object on the bed were cats, in this video, it was an actual person. How hard is it going to be to track him down? How dangerous is this man?