Turn on a Trail across all regions: You can now turn on a trail across all regions in the for your AWS account. CloudTrail will deliver log files from all regions to the Amazon S3 bucket and an optional CloudWatch Logs log group you specified. Additionally,when AWS launches a unusual region, CloudTrail will create the same trail in the unusual region. As a result, and you will receive log files containing API activity for the unusual region without taking any action. Using the CloudTrail console,you can specify that a trail applies to all regions. For more details, refer to the Applying a trail to all regions section of the CloudTrail FAQ.
Source: amazon.com