Observability in data workflows often stops at logs and metrics, leaving data lineage as a blind spot. At Booking, we set out to change that by treating lineage as a core observability layer. In this talk, I'll walk through how we integrated lineage tracking into our Airflow ecosystem, what metadata we capture, and how we surface it to users in a meaningful way. I'll also share how lineage data helps us debug failures, detect unexpected changes, and ensure compliance. You'll leave with a practical view of what it takes to make lineage not just visible, but actionable.