The Adler Planetarium, Art Institute of Chicago and Shedd Aquarium are going to be closed longer than originally thought for the NATO summit.

The popular Chicago tourist attractions will be closed a total of three days, from Saturday, May 19th through Monday, May 21st.

Andrea Smalec, a spokesperson for the Shedd, said museum officials decided it is best to stay closed given the security restrictions surrounding the summit.

“There’s a little bit of uncertainty still in terms of exactly the logistics and the pedestrian movement to and from campus and how that’s going to have an impact,” Smalec said.

Smalec said smaller crowds were already expected during the weekend of the summit.

Erin Hogan, a spokesperson for the Art Institute, said any time the museum has to close, it loses revenue. However, she said the move made sense given the road closures and parking restrictions.

A spokeswoman for the NATO host committee has said the museums will not be reimbursed for lost revenue.

The Field Museum is scheduled to be closed on Sunday, May 20th only.