Pylons are fictional items featured in the Land of the Lost multimedia franchise. Specifically, they relate to the original 1974-1976 TV series. Pylons first appeared in the pilot episode of the series, "Cha-Ka".
Pylons are large metallic obelisks that exist in the Lost Land of Altrusia. These alien constructs were originally designed by the prehistoric Sleestak and it is believed that they hold the key towards opening the dimensional portals between worlds.
A pylon is a hollow structure that can only be accessed by way of a hidden door that only materializes once an accompanying pyramid key is affixed to the flat surface wall of the pylon. Inside the pylon is a matrix table, decorated with various colorful gemstones, all of which serve a different purpose. Depending upon how the stones are arranged, a variety of effects may be caused. A spatial rift may be opened, which enables travelers to come and go from varying points in time. The pylons also have atmospheric properties and can alter weather patterns as well as change the rotation of the planet itself.
In one instance, travelers in the Lost Land had to use the pylon matrix table in order to correct the Earth's gravitational rotation to ensure that the sun and the moon would rise and set at appropriate times (LOTL: Blackout)
There are at least two known pylons. The Clock Pylon is the one that can control day and night. As Sleestaks are nocturnal creatures, it is in their best interests to keep things as dark as possible. However, the Library of Skulls informed them that an Eternal Night would spell the end of the Sleestak race. (LOTL: Blackout)
The pylons possess a natural defense field to protect itself. Attempting to damage the structure of the pylon itself will generate an electrical discharge that is strong enough to repulse even dinosaurs. The Tyrannosaur known as Grumpy learned this the hard way when he tried to eat a pylon.