Amazon S3 is storage for the Internet. S3 means simple storage service. S3 is highly-scalable, reliable (99.999999999% durable), low-latency data storage infrastructure and is offered at very low costs. S3 is object based storage and it can contain any kind of files ranging from 0KB to 5TB in size. S3 offers unlimited amount of data storage.
Objects in S3 can be directly accessed from the internet via URL if configured to do so. S3 can take care of any spikes in load and developers do not need to worry about the spikes in load.
When logged into AWS console, user creates buckets in a region and the data in S3 is stored in this buckets for the user. The data in the buckets are redundantly stored on multiple devices across multiple facilities.
Data is stored in a region which is chosen by the user. The user should choose a region depending on the proximity of the application using the data. AWS has data centers around the world and have regions in almost all continents including, Asia, America, Europe and Australia.