What is one major event that happened in To Kill a Mockingbird from Scout's perspective?

One event which has a significant impact upon Scout is hers and Jem's visit to Calpurnia's church.

When the children accompany Calpurnia to the African Methodist Episcopalian Church, Scout is amazed that the black community is too poor to afford paint for the church's ceiling, a piano or organ, hymn books, programs, or even sufficient lighting. Reverend Sykes mentions Tom Robinson and "his trouble," and then he has a collection taken up for the Robinson...

One event which has a significant impact upon Scout is hers and Jem's visit to Calpurnia's church.

When the children accompany Calpurnia to the African Methodist Episcopalian Church, Scout is amazed that the black community is too poor to afford paint for the church's ceiling, a piano or organ, hymn books, programs, or even sufficient lighting. Reverend Sykes mentions Tom Robinson and "his trouble," and then he has a collection taken up for the Robinson family who apparently cannot support themselves without him because, as Scout later learns from Calpurnia, no one will give Helen Robinson a job.

In addition to this new experience of seeing how poor the black community is, the children also experience racial bias and resentment against them as Lula protests their invading her private community when she accosts Calpurnia:

"I wants to know why you bringin' white chillun to nigger church." [sic]
"They's my comp'ny," said Calupurnia. (Scout also finds her way of talking strange)
"Yeah, an' I reckon you's comp'ny at the Finch house durin' the week."

Lula points to the racial discrepancies of the two cultures in Maycomb as Scout realizes that it is not just economic conditions from which Calpurnia's community suffers and feels resentment. Thus, she begins to learn about the racial problem in Maycomb.