Researchers may have discovered the world's biggest spider web, a massive subterranean structure spanning over 100 square meters in a sulfur cave on the Albania–Greece border. The multilayered web along a wall near the cave entrance is home to a colony of approximately 69,000 Tegenaria domestica (also known as the domestic house spider) and 42,000 Prinerigone vagans spiders. This is believed to be the first documented case of colonial web formation for both species.