Flat Earth
Flat Earth is the belief that geometric nature of the planet Earth is a plane. It often implies an elaborate conspiracy between the United Nations, Jews, NASA, and other governments or secret societies.
According to flat Earthers, the Earth doesn't revolve around the sun and the moon doesn't revolve around the Earth. Instead, the sun and the moon hovers in circles above the Earth's surface.
Often flat Earthers deny gravity in favor of an electromagnetic theory. Gravity is a myth and the reason that some objects sink while others float is due to density. It's not clear why density would matter if gravity doesn't exist.
Although the Earth is flat, flat Earth promotes the idea that it is covered by an invisible dome. The north pole is often located at the center of the dome, while the circumference of the dome is considered to be the south direction.
The reason why it is impossible to travel beyond the circumference of the Earth is because it is surrounded by a giant wall of ice. In addition, it is heavily protected by government entities to prevent civilians from discovering the true nature of the Earth.