Updated 05/09/12 – 5:40 p.m.

CHICAGO (CBS) — The Shedd Aquarium, the Adler Planetarium, and the Art Institute of Chicago will be closed for three days on the weekend of the NATO Summit.

The Secret Service had already announced those three museums and the Field Museum would be closed on Sunday, May 20, as part of the security measures surrounding the summit. On Wednesday, the Shedd, Adler and Art Institute announced they would also be closed on Saturday, May 19, and Monday, May 21.

The Field Museum, however, will remain open on May 19 and May 21.

“Collectively, the institutions strongly support and welcome the Summit and its international delegation to the city as it showcases Chicago’s great offerings to the world. For the clarity and convenience of museum guests, the additional operational adjustments were made with the consideration of each organization’s close proximity to McCormick Place and other designated event areas,” Museum officials said in a joint statement on Wednesday.

CBS 2 Chief Correspondent Jay Levine reports the decision to close three major museums between Saturday and Monday is unheard of, especially during the start of a busy tourist season.

It’s the late-breaking, last-minute security arrangements which seem to have everyone in a dither, with no uniform policy about opening of closing of some of Chicago’s top attractions.

“It’s an inconvenience. I said then, and I’ll say again, I don’t minimize it,” Emanuel said Wednesday.

It’s especially an inconvenience for the city’s Museum Campus, with road closings and parking bans for much of the weekend.

That’s not stopping the Field Museum from staying open for as long as possible. It will only close on the Sunday of the summit, because of the security measures being taken by the Secret Service, and only because it’s hosting a still-unannounced NATO event.

Field Museum spokeswoman Nancy O’Shea said there were discussions about closing the Saturday and Monday of the summit, but “we decided, after talking to the NATO officials that we could be open on Saturday, the 19th, and on Monday, the 21st. And that’s what we’re going to do.”

But, just across the street, the Shedd Aquarium and Adler Planetarium both will completely shut down the Saturday, Sunday and Monday of the summit weekend.

Shedd Aquarium spokesman Roger Germann said they consulted with the Secret Service about their decision regarding whether to close during the summit. Although the Secret Service did not recommend closing on Saturday and Monday, Shedd officials decided it was the best move, given the uncertainty about how the summit will affect traffic in the area.

The mayor, asked again Wednesday about street closures in the South Loop and moves to shut down parts of Lake Shore Drive and the Stevenson Expressway for the summit, was confident disruptions would be minor.

“We’ll be able to handle it, the community is able to handle it, our police department’s able to handle it,” he said. “It’ll be for two-and-a-half days and our city will continue to go forward.”

Even though the Shedd Aquarium, for example, will lose between 15,000 and 20,000 visitors that weekend, officials said they feel it’s worth it.

“Last year, we did 2.1 million people. Half of those people came from 4 hours or more away, around the country, as well as our international travelers,” Germann said. “So, if we put on a really good conference, we feel those folks will come back, and the benefit definitely outweighs a 72-hour inconvenience.”

The museums will be open as normal through Friday, May 18, and will reopen on Tuesday, May 22, the day after the summit ends.

Navy Pier, the city’s largest tourist attraction, will stay open for its normal hours during the entire NATO summit, according to a spokesman.

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