With its increasing popularity among tourists, one of Washington’s newest museums is now leaving its doors open later and changing the way people can buy tickets to get inside.

Visitors to the International Spy Museum will now be allowed to purchase advanced tickets through Ticketmaster before their arrival. In the past, tickets could only be bought at the door, leading to long lines lasting for sometimes more than three hours.

“This is great because it will reduce the lines to less than an hour,” said Jennifer Saxon, a spokeswoman for the museum. “It will dramatically improve the wait.”

The museum estimates that 3,000 visitors travel to the museum every day of each weekend, while at least 2,000 people visit to the Spy Museum on any given weekday.

Before it opened less than nine months ago, officials at the museum expected 500,000 visitors to walk through within its first year. But the museum has already welcomed more than that number to learn about spy technology and the like.

The new advance tickets will all be date and time specific. Tickets are $13 for adults, $10 for children ages 5-18 and $12 for senior citizens and active military duty or intelligence officials. Children 4 and under are admitted for free.

In addition, the Spy Museum will now open at 10 a.m. until the last admission at 7 p.m. daily. The museum closes one hour after the last admission.