Many of the most majestic or particularly cartoon-like buildings around D.C. are open to the public—often for free. But one of the most beguiling buildings on the Beltway has only been accessible to Mormons since it opened in 1974.

All of that will change, if briefly, when the Mormon temple in Kensington, Md. has a public open house once it completes a modernization effort in 2020.

The Church of Jesus Christ of Latter-Day Saints announced that the temple is undergoing renovations starting in March 2018, in a release flagged by Bethesda Beat.

The 160,000 square foot building, sheathed in 173,000 square feet of Alabama white marble, is getting upgrades to its mechanical and electrical systems, along with a refurbishment of “all finishes and furnishings,” per the LDS church. The temple’s groundbreaking was nearly 50 years ago, and it serves Mormons in D.C, Maryland, Virginia, West Virginia, and Pennsylvania. At 288 feet, it’s the tallest of the LDS Church’s temples.

It underwent repairs in 2011 following the 5.9-magnitude earthquake that shook the region, causing four of the temple’s six spires to lose their tips

While Mormon meetinghouses and chapels permit those of different faiths to enter, temples are reserved for members of the LDS church to participate in sacred ceremonies. An annual Festival of Lights brings visitors to the grounds to see hundreds of thousands of Christmas bulb decorations and into a visitor center, but not the temple itself.

The first dedication of the Washington D.C. Temple in 1974 also brought a slew of non-Mormons to the building, including then-First Lady Betty Ford.

According to the church, 758,328 people attended the first public open house, and the tours led to more than 75,000 missionary referrals.

Visitors will find a 30-foot mural depicting the second coming of Jesus Christ in the main lobby, stained glass “with rich, vibrant reds and oranges giving way to more translucent blues and violets and finally white [to] represent the unbroken progress toward the divine available in the gospel and the purity that enters one’s life as he rises above earthly cares and reaches heavenward,” and other architectural and design features.

The church will announce more details about the public open house and rededication ceremony when work on the temple is nearly complete.