How would you architect a highly available, multi-region AWS deployment?

Multi-region HA involves several layers:

1. DNS: Route53 with health checks and latency/failover routing policies to direct users to the nearest healthy region.
2. Data replication: RDS Multi-Region Read Replicas with promotion capability. DynamoDB Global Tables for active-active.
3. Edge: CloudFront CDN with origins in multiple regions.
4. Infrastructure: Identical infrastructure in each region managed by Terraform.
5. DR strategy: Define RTO (Recovery Time Objective) and RPO (Recovery Point Objective) to determine your architecture (Pilot Light, Warm Standby, or Active-Active).