On March 1 2007, students at schools around the world marked the advent of International Polar year by conducting an ice experiment. They then told the IPY community and the world by pinning a virtual balloon onto a web-based map showing exactly where they were.

It proved to be quite a success, with hundreds of schools contributing so far. IPY enthusiasts also joined in, turning the map into a riot of red balloons.

See the whole map here.

For technical reasons, browsers don't like it if you show too many balloons at one time, so only the most recent 200 balloons are shown. However, you can see all contributed posts directly by browsing the directory from this page. Navigate to older balloons at the bottom of the page.

You can also always see the most recent balloons in your view using Google Earth and this link.