It's been 5 years since Google first introduced the Google Maps API, a move that has brought Google Maps to more than 350,000 websites worldwide, and this week the company is celebrating the API's birthday with a map of Google Maps mashups.

The Maps API is implemented using JavaScript and, before it was made available by Google, many developers embedded Google Maps onto their websites by reverse engineering code. Adrian Holovaty, one of the pioneers of creating Google Maps mashups, tells of how he used to have to create hacks to embed maps.

When Google Maps launched -- with maps assembled client-side, in JavaScript! -- I was one of the band of tinkerers around the globe who poked at Google's obfuscated code until we figured out how to embed their maps in our own pages. It was a ton of fun, not only doing the reverse engineering, but seeing the various discoveries and hacks other people were making: embedding multiple maps in a single page, swapping out the map tiles, using custom map markers, making markers move, loading real-time data onto maps...These days, it's hard to fathom a Web without embeddable maps. Wasn't it always that way? To Google's eternal credit, instead of shutting these hacks down, they recognized the demand and legitimized it in the form of their mapping API.

According to the Google Geo Developers Blog post, nearly half of the almost 5,000 mashups on Programmable Web's dashboard use the Google Maps API. In an effort to show the widespread influence of the API, Keir Clarke from Google Maps Mania created a mashup of mashups that we've included below. From real-time tracking of buses in NYC to mapping out news down to a block-by-block level, the mashup shows where across the world Google Maps mashups have been created using the API.