In tonight's The White House: Mysteries at the Museum, host Don Wildman heads to Washington, D.C. to find out how the White House evolved from a comparatively humble, 18th-century sandstone building into the high-tech national nerve center it is today. Here’s a taste of what awaited him there.

1: Abraham Lincoln never slept in the Lincoln Bedroom.

For the first hundred years of its existence, the White House didn’t have purpose-built offices, and each president had to choose a room to work in—usually a converted bedroom upstairs. Lincoln used what became known as the Lincoln Bedroom as his office.

2: President Harrison tried to turn the White House into a castle.

No, seriously: According to the reference branch of the National Archives, President William Harrison proposed to quadruple the building in size (and finally separate the public and private areas once and for all) by creating an enclosed court and adding offices for the staff and an art wing for visiting tourists. Congress refused to pay for it.

3: Teddy Roosevelt nearly brought the whole place down.

In 1902, President Roosevelt spearheaded a renovation that turned the entire second floor of the White House into private living space, moved the public entrance to the east, and moved the executive offices to a western wing. His “restoration” was largely faithful to the building’s 1792 design, but its expansion of the dining room to seat more guests removed a load-bearing wall. The house’s structure was overstressed for the next 50 years, and a piano leg burst through the ceiling in 1948 (much to President Harry Truman’s surprise).

4: Truman’s work to update Roosevelt’s renovation job might have connected the White House to a bomb shelter.

After a piano nearly relocated itself in the dining room and engineers reported that the White House was in danger of collapsing, Truman ordered a gut renovation. Everything but the stone walls was demolished, a new steel frame was built and a two-level sub-basement was added. Did a concrete tunnel connect the sub-basement to a shelter FDR built during World War II? Construction photos of the excavation and tunnel exist, but the relationship between them remains a mystery.

5: Yes, the White House still uses hotlines.

While the widely reported on Moscow-Washington connection using a "red phone" -- a thing of fiction -- is usually the first thing we think of when we consider hotlines in the White House, it's not the only one. A direct connection between the U.S. and India's Prime Minister Narenda Modi was established via a hotline in 2015, though it has yet to be used. One hotline that is definitely used? The direct line to the White House for leaving comments for the president is still a popular form of communication, operated by volunteers chosen by the administration.

6: We don't know how many Secret Service agents guard the White House.

While the Secret Service says it employs more than 1,300 Uniformed Division officers to stand guard at 1600 Pennsylvania Avenue and various embassies around Washington D.C., it does not publicly share the number of those agents specifically assigned to protect the White House grounds. And the dogs you sometimes see standing guard with them? Those are Belgian Malinois canines brought over from Holland and trained under a program started in 1975. They stay with those Uniformed Division officers 24 hours a day and are retired to their longtime handlers, usually when they turn about 10 years old.

7: The sky over Washington is a strictly (and dramatically) enforced no-fly zone.

In order to take a helicopter ride over the city for filming The White House: Mysteries at the Museum, Don underwent a background check and had to receive clearance from three different federal agencies. Air traffic in the area was heavy until 9/11, when the White House was a suspected target of Al Qaeda’s attacks. There’s now a no-fly zone 10 miles wide over the president’s residence that is surrounded by a laser warning system. If a pilot ignores the system's warning, a fighter jet will escort them to the nearest runway.

The White House: Mysteries at the Museum premieres tonight at 9|8c on Travel Channel.