Sky History 2 HD Saturday

Experts visit an ancient fortress in Peru believed to have been built by aliens using tools far more advanced than those thought to have been available to humans at the time

Experts investigate alleged sightings of UFOs during the Black Death, and examine the theory that aliens may have inflicted the disease on the human race

Bettany Hughes relives opening day at Rome's Colosseum - the first day of the inaugural games held by Emperor Titus, where the people could revel in the bloodthirsty entertainment

The veteran actor examines the notion that there are UFO hotspots at various locations around Earth, contemplating why this might be the case

Documentary going behind the scenes at the castle and exploring its history. The first episode focuses on the Beefeaters and reveals the origins of the tower

Lorraine Kelly explores the nation's constant harking back to Winston Churchill and the part played by Britain in the Allied victory in the second World War