An api mash up with google maps/places API.
Some more details on what a Web API is.
A web Application Programming Interface or API is a interface to a request-response server, typically via JSON or XML, that can be accessed from the internet. Web applications generally mash up multiple APIs and combine them to create a sum greater than its parts.
APIs connect your website with remote services to easily enhance the end user experience by allowing a web site to access extensive databases and enhanced services that will bring your site to the next level.