Amsterdam's canals are famous for hiding more than eight centuries of history in their mud. From 2003 to 2012, archaeologists had the rare opportunity to dig through an urban river that had been pumped dry, and now 99% Invisible reports that their discoveries are available to browse online.

The new website, dubbed Below the Surface, was released with a book and a documentary of the same name. The project traces the efforts of an archaeological dig that worked parallel to the construction of Amsterdam's new North/South metro line. To bore the train tunnels, crews had to drain part of the River Amstel that runs through the city and dig up the area. Though the excavation wasn't originally intended as an archaeological project, the city used it as an opportunity to collect and preserve some of its history.

About 800 years ago, a trading port popped up at the mouth of the River Amstel and the waterway become a bustling urban hub. Many of the artifacts that have been uncovered are from that era, while some are more contemporary, and one piece dates back to 4300 BCE. All 700,000 objects, which include, toys, coins, and weapons, are cataloged online.

Visitors to the website can look through the collection by category. If you want to view items from the 1500s, for example, you can browse by time period. You also have the option to search by material, like stoneware, for example, and artifact type, like clothing.

After exploring the database, you can learn more about its history in the Below the Surface documentary on Vimeo (English subtitles are coming soon).

[h/t 99% Invisible]