Pennsylvania is one of 13 states in which teacher strikes are legal.

The district has been plagued by teacher strikes.

The district has had an unusual number of teacher strikes, with walkouts in 1972, 1977 and 1990.

With 48,000 students, Sacramento is the biggest district in the country to have a teacher strike.

Pictures of the 1980s teacher strikes posted to Flickr by "union person"

Buffalo is not the only region in the Northeast facing a teacher strike.

"How many of you are sick of this teacher strike?"

Under state law, the Board of Education must withhold two days' pay for every day that a teacher strikes.

Through the years there have been many bitter teacher strikes and too many student protests to count.

Although teacher strikes were illegal, teachers in Norwalk went out on strike at the same time.