The slag heap (Halde) at Beckstrasse in Bottrop is one of the biggest in the Ruhr area. Its height of approximately 60 metres meant that is was predestined for a special kind of slag heap event – the tetrahedron. This creation by architect Wolfgang Christ is a monumental look-out tower in the form of a pyramid which can be climbed by visitors. Because it can be seen for miles around, the tetrahedron has become a landmark for the people of the region and its visitors. The 50-metre-high steel construction above the plateau of the slag heap rests on four columns. Viewed from afar, it thus seems to be “hovering” despite its ton weight.

The tetrahedron occupies the surrounding “artificially” shaped slag heap landscape like a surreal sign. While it is a geometrical copy of a pyramid, it is a filigree and transparent structure rather than a solid one.

At night, the “slag heap happening” becomes a “light happening”. Düsseldorf artist Jürgen LIT Fischer transformed the top of the tetrahedron pyramid into a bold “light sign” made of yellow and green lines of light.

The “light sign” above the slag heap thus shows the tetrahedron to be a place where views in a wide variety of directions reflect the diversity of the surrounding colliery landscape and yet enable visitors to experience the panorama as a unified whole.

Tetraeder – Haldenereignis Emscherblick ( – Onlinemagazin für das Ruhrgebiet)
Tetraeder (Bottrop-Tourismus)