2 The Time Tunnel (1966-1967)

The Time Tunnel was another Irwin Allen production. The premise follows the U.S. government effort to construct a time machine for the top-secret Project Tic-Toc. The too-on-the-nose experiment is hidden 800 floors deep beneath Arizona, where the cost and utility of the Time Tunnel is debated.

When two scientists are plunged into the vortex of time, falling into one place in history after the next, the government continues to fund the project to bring the scientists home. The show was canceled before the filming of the scientists' safe return.