For the youth of America that came of age at the dawn of the 20th century, education was an iffy proposition. Only half of those aged 5 to 19 years old in 1900 even attended school, and only 62,000-6.4 percent of 17-year-olds-graduated from high school.

Most students walked to a school that typically consisted of one room. On cold days, students might have had to help load the school's wood stove to provide warmth.

A lone teacher instructed children of varying ages in courses such as reading, writing, arithmetic and history. Students sat in uncomfortable wooden benches and screeched out writing onto slate boards.

One hundred years later, that school experience is unrecognizable to the millions of students who fill U.S. classrooms. From the buses and cars that bring them to schools, to the better trained teachers that greet them in their classrooms, to the sophisticated technology that gives them instantaneous access to an unending gusher of information, today's students have tools and resources available to them that the student of 100 years ago couldn't begin to imagine.

As the 20th century draws to a close, it's clear that the dizzying changes of the last 100 years have left a mark on education and the school buildings that have welcomed billions of students.

Meager beginnings

Public education in 1900 was, by modern standards, lacking. In Brown v. Board of Education, the landmark opinion that outlawed racially segregated schools, U.S. Chief Justice Earl Warren described the inadequacies of public education at the turn of the century.

"In the South, the movement toward free common schools, supported by general taxation, had not yet taken hold," Warren wrote. "Education of white children was largely in the hands of private groups. Education of Negroes was almost nonexistent....(I)n the North...the curriculum was usually rudimentary; ungraded schools were common in rural areas; the school term was but three months a year in many states; and compulsory education was virtually unknown."

In the early years of the 20th century, children began to stay in school longer. High school enrollment climbed from 519,000 in 1900 to 6.6 million by 1940. The Great Depression, which left millions of adults unemployed, also dried up the job market for teenagers. More of them stayed in high school.

Many states enacted compulsory attendance laws. Society began to take for granted that free public education would be available for its children.