This ICDP drilling project sends a drilling rig to a carefully chosen site, on land or at sea, to bore deep into the Earth’s crust and retrieve rock cores and fluid samples. By studying these materials, scientists try to read the planet’s history written in rocks and sediments: how the crust formed and moved, how fluids travel through rocks and influence earthquakes and volcanic activity, and how climate and life left records in sediments over millions of years. The site is picked to answer a specific question, such as how faults behave, what chemical and magnetic clues reveal about past environments, or how the layer beneath the crust interacts with the surface. The aim is to improve our understanding of natural hazards, long-term climate change, and the inner workings of our planet. The knowledge helps scientists forecast hazards, interpret past events, and guide resource management.