The Proterozoic era, spanning from 2.5 billion to 541 million years ago, left behind remarkable geological formations, including stunning basalt sculptures that have inspired outdoor art. Among the most famous is the Giant's Causeway in Northern Ireland, a UNESCO World Heritage Site featuring hexagonal basalt columns formed by ancient volcanic activity. Another notable example is the Devil's Postpile in California, USA, where towering basalt columns create a mesmerizing natural sculpture.

In Iceland, the Reynisdrangar basalt sea stacks rise dramatically from the Atlantic Ocean, shaped by erosion over millennia. India’s St. Mary’s Islands boast unique basalt rock formations, often compared to the Giant’s Causeway. These ancient sculptures not only showcase Earth’s geological history but also serve as open-air galleries for nature’s artistry. Visitors and geologists alike marvel at these prehistoric masterpieces, which continue to captivate with their timeless beauty.