Mexico’s Teotihuacan, once the center of a sprawling pre-Hispanic empire, is set to become the launch pad for an attempt to communicate with extraterrestrial life.

Starting on Tuesday, enthusiasts from around the world will have a chance to submit text, images, video and sounds that reflect human nature to be included in the message.

Those contributions–part of media company Yahoo’s “Time Capsule” project–will be digitized and beamed with a laser into space on Oct. 25 from the Pyramid of the Sun at Teotihuacan, now an archeological site near Mexico City.