Bryan Lynn

About half of students age 13 to 15 worldwide have experienced violence in school, including bullying, corporal punishment, school shootings and war, a U.N. report said. "For millions of students around the world, the school environment is not a safe space to study and grow," the UNICEF report said. "It is a danger zone where they learn in fear." Bullying is one of the biggest problems in schools, with 1 in 3 students experiencing it, the report said.

As American students head into a new school year, a shortage of teachers — which reached a 10-year low in 2016 — is a major problem for an increasing number of U.S. states. In some states, there is especially a great need for teachers of special education, science and math. In others, schools are not finding enough qualified language teachers. In general, the U.S. has seen increased demand for teachers in recent years.

As American students head into a new school year, a shortage of teachers — which reached a 10-year low in 2016 — is a major problem for an increasing number of U.S. states. In some states, there is especially a great need for teachers of special education, science and math. In others, schools are not finding enough qualified language teachers. In general, the U.S. has seen increased demand for teachers in recent years.