On this Thursday's all-new episode of Fringe, Peter and Oliiva take a trip to Pennsylvania in order to investigate the world's worst underground tunnel. It's full of human remains.

Meanwhile, Walter conducts an experiment that's rather unusual, even for him: he uses frogs to travel between realities.

Get caught up on last week's installment, via our collection of Fringe quotes, and then click on the photos below for an early look at "Night of Desirable Objects."

For a preview of the new episode, follow this article's jump.

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Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.