HELENA, Mont. (AP) — A shortage of bus drivers is complicating the start of a new school year already facing a surge in COVID-19 cases and conflicts over whether masks should be required in school buildings.

School districts are offering hiring bonuses, training to get commercial driver's licenses and pay increases in an effort to attract more drivers.

First Student contracts with school districts across the country to provide bus service, and held test driving events this summer.

Its “Big Bus, No Big Deal” events were an effort to show people that driving a bus is not as difficult as people might think.

Inside Amazon: A Detailed History of America's Biggest Online Retailer

Stacker compiled a list of key moments in Amazon's history and its current business from a variety of sources. Here's a look at the events that turned an online bookstore into a global conglomerate and a self-made entrepreneur into the world's second-richest man.