KANSAS CITY, Mo. — An obelisk of incredible historic significance stands unceremoniously under a tree outside an abandoned high school in the Brookside neighborhood.

It’s a slab of the White House more than 200 years old. Now, what was once a piece of the nation’s most revered government building is simply an unmarked pillar of gray, aging stonework.

Anne Kniggendorf, author of “Secret Kansas City,” explained how the slab got from Washington D.C. to KC nearly 70 years ago.

She said Southwest High School near 65th Street and Wornall Road opened nearly 100 years ago, but it closed in 2016. However, she said the school is home to a lot of famous alumni, including the founders of H&R Block and rap artist Tech N9ne.

“One of the guys was friends with President Truman: Henry Talge,” Kniggendorf told FOX4. “When Truman remodeled the White House, he started handing out bits and pieces of the parts that he tore down.”

Talge has been pictured with President Truman several times. An image with the Truman Library shows Truman blowing out a birthday candle alongside Talge.

From 1948-1952, Truman lead an expansive renovation and extension of the presidential mansion, according to the White House Historical Association. The White House seen today is mostly a result of this massive mid-century project.

“Henry’s grandson went to Southwest [High School] also… and he loved this track coach named Coach House,” Kniggendorf said.

She said the coach died in the mid-1950s, and the slab was donated to the school as a memorial.

“The plaque for it is way, way over there on the flag pole, which they moved in the 1960s apparently so it would be more visible!” Kniggendorf said incredulously, pointing to the other side of the track beyond the fence.

The White House was originally constructed in 1791. It was burned in 1814 by the British, but it was reconstructed and added onto throughout the first half of the 1800s.