。
My parents let me go there.
Literal
Parents [topic-は] me [object-を] there [toward-へ] let-go [for-me-てくれた].
行かせてくれた combines the causative (行かせる) with てくれる (did it as a favor for me). This shifts the meaning from coercive to permissive: 'they let me go (and I'm grateful).' The てくれる is what signals permission-as-kindness.