Mitt Romney gets an unexpected surprise. (Felicia Sonmez/Washington Post via Instagram)

MOON TOWNSHIP, Pa. -- Mitt Romney walked out of his campaign jet at Pittsburgh International Airport here Tuesday afternoon and was met by an unexpected sight: hundreds upon hundreds of supporters packed into the top and middle levels of a nearby parking garage, cheering the candidate's arrival.

A visibly moved Romney, clad in a white shirt and slacks, stepped into the late afternoon sun and walked across the tarmac to a spot near a metal fence separating him from the supporters in the garage.

Press entourage in tow, he waved to the crowd for several moments, saying nothing.

Afterward, a reporter asked Romney how the moment made him feel.

"That's when you know you're gonna win," he said as he walked back across the tarmac and into an SUV that carried him off to his second stop of the day.

The moment came two days after he held a rally across the state, near Philadelphia, that drew tens of thousands of supporters who braved freezing temperatures to see the Republican candidate.

Both events were a reminder of the gamble that Romney has made in Pennsylvania, a state that has eluded GOP presidential candidates for decades where Romney, like Sen. John McCain (R-Ariz.) before him, has launched an 11th-hour effort

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