PITTSBURGH (KDKA) — Many of us pass historic churches, grand former train stations, and other public buildings every day without ever looking inside.

So, how does a performer’s view of Heinz Hall sound?

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“For ‘Doors Open Pittsburgh,’ this weekend only, you’re going to be able to actually stand on stage and look outward,” says event founder Bonnie Baxter.

She says the tour, open in most locations both Saturday and Sunday, features free visits to 39 downtown locations.

“It’s providing an opportunity for people to come in and visit buildings that we all drive past, walk past, may have heard about, but never took the time to know,” said Baxter.

Buildings like the Harvard-Yale-Princeton Club, one of the city’s oldest buildings. Chef Chuck Kerber cooks, farm to table, and you don’t have to be an alumnus to join.

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Underneath the grand lobby of the Omni William Penn Hotel, the “Speakeasy” was almost “untouchable.”

“‘The Speakeasy’ was a popular place during prohibition, here at the hotel,” says general manager Bob Page.

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The lush hideaway led to a secret tunnel, where illegal imbibers escaped police raids.

Dollar Bank Vice President Sandra Wise says a pair of lions outside the bank are copies of originals, now tucked inside the ornate building that dates back to 1871.

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Across Fourth Avenue, the Engineers Society Club was formerly a bank. For privacy, a dinner table in the vault has the right combination.

For a change of pace, Joe DePietro, of Pitt, introduces Aquaponics, at Liberty and Penn.

“In this big tank here we have around 100 fish, all swimming around,” he says, standing inside the temporary two-story structure. “We feed them. They excrete waste. The waste filled water is the perfect environment for plants to grow in.”

The water is pumped up to vertical flower towers on the roof.

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For more information on “Doors Open Pittsburgh,” visit www.doorsopenpgh.org.