Perhaps their most famous prediction occurred nearly two years before planes flew into the World Trade Center and the Pentagon Sept. 11, 2001. The sisters appeared on the Art Bell Radio show and can be heard predicting possible terrorist attacks on the federal government and the World Trade Center.
"We both had written exactly in detail all of the events of 9/11 and even the simultaneous attack on the Pentagon," Terry said.
Although some of their predictions have been tough to independently confirm, the twins say they use the powers for the purpose of helping others, not for financial gain.
"We don't buy stocks and we don't gamble," Terry said. "We were taught that if you do it to become wealthy, you would lose the gift."
"The gift is for other people," Linda added.
Find out more on "Primetime Nightline: Beyond Belief" Wednesday at 10 p.m. ET/PT.