Short answers, pulled from the story.
Agnes Ozman first spoke in tongues on the first day of January 1901 at the Bethel Bible School in Topeka, Kansas. This event confirmed Charles Parham's theory that speaking in tongues was the biblical evidence of receiving the baptism with the Holy Spirit. The occurrence marked the birth of the Pentecostal movement.
The Azusa Street Revival began on the 14th of April 1906 at a former warehouse located at 312 Azusa Street in Los Angeles. William J. Seymour led the prayer meetings that started at 214 Bonnie Brae Street before moving to the warehouse. This three-year event is considered the birthplace of modern Pentecostalism.
The theological split in 1910 involved the doctrine of sanctification articulated by William Durham. The Finished Work doctrine held that sanctification occurred at the moment of salvation, while Holiness Pentecostals taught it was a second work of grace. This disagreement created a permanent schism between Holiness Pentecostals and Finished Work Pentecostals.
Pentecostalism has over 279 million classical Pentecostals and a total of over 644 million adherents when including the Charismatic movement. This makes it the fastest-growing religious movement in the world. The growth has shifted the center of gravity of Christianity from the West to the Global South.
Classical Pentecostals often formed their own denominations while the Charismatic Movement brought Pentecostal beliefs into existing Catholic, Protestant, and Orthodox churches. The Charismatic Movement emerged in the 1960s and sought to renew traditional churches from within. Despite differences, the two movements have increasingly merged with over 644 million adherents globally.