When the people of Amsterdam commited a serious enough crime from 1360 untill 1795, they would be publicly executed at Dam Square and - later - at the Nieuwmarkt (New Market). Their bodies would then be moved to the other side of the IJ, where they would be put on display for everybody to see. This was done at the Galgenveld (Field of Gallows).
The location of the Galgenveld can be seen on the map below where the green area is the land mass of ‘Volewijck’ around the year 1860 projected on an aerial photo of the current situation (2017). You can see that the Galgenveld was located almost at the exact same spot as where you are standing now. The location was picked specifically because at this spot the crew of the ships that sailed into the harbor of Amsterdam would get a clear warning to not do anything stupid or else they would end up hanging there themselves.
Probably the most famous person to be displayed at the Galgenveld is Elsje Christiaens. She was a servant from Denmark and got into a fight with her land lady about the rent. She eventually killed the poor woman with an axe. As was customary those days the murder weapon would be placed next to the rotting body. This can be seen in the case of Elsje on this drawing by Rembrandt van Rijn dating from 1664.
Believe it or not but the Galgenveld is historically seen as the first public attraction of Amsterdam. People would come from afar to have a look at the often gruesome display. The hanging bodies were left to rot for a long time and were slowly decaying by the weather. After a while when they needed the space for other bodies to hang, the remains would be thrown into the pit, which can be seen in the very first picture. In this pit they would decay further while being eaten by birds, bugs, worms and snails. Yes, snails...
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