Azusa Street is the usual starting point for Pentecostalism, now among the largest movements in world Christianity, and it earned the position: the mission published a paper that circulated widely, visitors came from across the United States and abroad, and missionaries left directly from its meetings for Africa, Asia and Latin America within months.
Historians have nonetheless complicated the single-origin account. Revivals with comparable phenomena occurred independently in Wales in 1904, in India at around the same time, in Chile and in Korea, and the holiness movement out of which Pentecostal teaching grew was already international. Some of these had no connection with Los Angeles at all. The current scholarly picture is of multiple beginnings, with Azusa Street as the most influential node in a network rather than the sole source, and this matters for how the movement understands itself outside the United States.
The racial history is also part of the record and did not end well. The integration of the early meetings did not survive the institutionalisation that followed, and the denominations that formed out of the revival within a decade were largely separated by race, a division that white Pentecostal bodies formally repented of only in the 1990s. That an interracial revival produced segregated churches within twenty years is a fact about American religion rather than about Pentecostal doctrine, and it belongs in the account.