AWS CloudTrail is a web service that records activity made on your account and delivers log
files to an Amazon S3 bucket
CloudTrail is for auditing (CloudWatch is for performance monitoring)
S3 Event Notifications is a feature that notifies you when certain events happen in your S3
buckets, it does not record API activity at the account level
Amazon CloudWatch Logs lets you monitor and troubleshoot your systems and applications using
your existing system, application and custom log files