The Masonic Temple of Philadelphia is celebrating its 150th anniversary and is gearing up for a rededication ceremony next month.

The building, located right next to City Hall, serves as the headquarters of the Grand Lodge of Pennsylvania and is a National Historic Landmark. Since 1873, the Masonic Temple in Philadelphia has drawn in Masons and non-Masons alike, serving as a meeting place for 28 other city lodges and as a venue for weddings, galas, and corporate events.

Conspiracies have swirled around Freemasonry for centuries, centering around the group’s alleged power and the secrets members tend to keep to themselves.

Michael Ernst has been a Freemason for nearly a decade and helps lead tours at the Masonic Temple. He said the mystique surrounding the group stems from conspiracies, including the common one associated with the Illuminati.

“The Illuminati were a masonic group that existed for a very short span of time in Germany, but they became very powerful that the state suppressed them,” Ernst said. “They were becoming very powerful at the time, even though they only lasted for about 30, 40 years.”

Mike Comfort, the director of the Masonic Library and Museum of Pennsylvania says some visitors who stop by the Temple are often surprised they’re allowed to come in.

“A lot of them recently have said, ‘Oh, this is new, that you’re letting people in,’” Comfort said. “I said, ‘Well, I hate to tell you this, but this building’s been open to the public for tours since the day it was dedicated in September of 1873.’”

The only time it wouldn’t be open to the public was when it rained back in the 19th and 20th centuries.

“Back then, before we all had cars, people had horses,” Comfort said. “And when the rain mixed with what horses leave on the streets, they didn’t want people bringing it in on their feet and ruining the carpet.”

On June 4, free tours will be offered every 20 minutes, from 9:30 a.m. to 10:50 a.m. and again from 1 p.m. to 3:20 p.m.

A cornerstone rededication ceremony will take place June 24 at 2 p.m. Cornerstones are a symbol “of the individual Mason and the sacrifices of labor and time necessary to build a moral and Masonic edifice.” One of the PA Grand Lodge’s notable members, Benjamin Franklin, created the tradition beginning with the cornerstone laying of the state house in Philadelphia.

Free tours will also be available after the event. Plans to continue free tours through the rest of the year are being discussed.

Freemasonry is one of the world’s oldest fraternal organizations and is based on the “radical proposition that men of different faiths can agree on God’s existence.”