This is a simple concept to go over at the high level. Cloud Front is what’s known as a Content Delivery Network, it is placed at the 216 and possibly growing edge location all over the world and what it does is it allows users to connect to the Cloud Front endpoint closest to them and then it accesses its cached information to deliver it directly to the user. If the CloudFront endpoint doesn’t have it cached it will reach out to the bucket or HTTPS server and cache it if another user wishes to access that information. This is great for static content you wish to have low latency for world wide. In short CloudFront acts as a Content Delivery Network with hundreds of edge locations all over the globe that allow users low latency by accessing cached information. S3 Cross-Region replication is a better option if the content is updated consistently and you need to set up access in select regions. CloudFront is also an excellent way to make private objects in S3 accessible through CloudFront.