Contractors for the OKC public schools made a startling discovery of an unintended time capsule dating back to 1917 as they were tearing out old chalkboards during a renovation project.

Teachers and students scribbled the lessons — multiplication tables, pilgrim history, how to be clean — nearly 100 years ago. And they haven’t been touched since.

This week, contractors removing old chalkboards at Emerson High School in Oklahoma City made a startling discovery: Underneath them rested another set of chalkboards, untouched since 1917.

“The penmanship blows me away, because you don’t see a lot of that anymore,” Emerson High School Principal Sherry Kishore told the Oklahoman. “Some of the handwriting in some of these rooms is beautiful.”

The chalkboards being removed to make way for new whiteboards are in four classrooms, according to the Oklahoma City Public School District.

A spokeswoman said the district is working with the city to “preserve the ‘chalk’ work of the teachers that has been captured in time.”

A wheel that apparently was used to teach multiplication tables appears on one board. “I have never seen that technique in my life,” Kishore told the Oklahoman.

The boards carry not just teachers’ work, but also that of students, and every room has a lesson on pilgrims, according to the district.

“Their names are here; I don’t know whether they were students in charge that day that got to do the special chores if they were the ones that had a little extra to do because they were acting up,” Kishore said. “But it’s all kinds of different feelings when you look at this.”

This article was written by Elahe Izadi and originally published on the Washington Post. Be sure to follow Elahe on twitter!