But the underwater discoveries that await aren’t only of interest to mapmakers or marine researchers. Far below the ocean’s surface lies buried treasure: precious metals, rare earth elements, oil and diamonds – riches that have, until now, remained inaccessible to even the most intrepid of prospectors.

Some ecologists fear that a map of our sea floor will allow extractive industries the chance to profit from these resources, potentially endangering marine habitats and coastal communities in the process. A global bathymetric map – that is, a map of the ocean’s floor – would certainly offer a better understanding of our blue planet, but it also might plunge us into a realm once reserved for science fiction: robot submarines, underwater volcanoes, sea jewels, coral with pharmaceutical properties, Wild West maritime law, toxic sediment plumes, and an ocean-based enterprise curiously devoid of humans or ships. Once the map is made, will it be used as a tool for responsible management and conservation, or wielded like pirate’s bounty, a guidebook to extraction and exploitation?

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Only 15% of the Earth’s ocean is mapped. Zoom in on the middle of the Pacific in Google Earth, for example, and you’ll find a representation of the ocean floor based on satellite and gravity-derived bathymetry: low resolution, indirect, often inaccurate. Considering that we’ve plotted our Solar System and charted the human genome, it’s rather astonishing that no map of the seafloor exists. But the reason is simple: our planet’s oceans are vast, deep, and largely impenetrable, and water literally gets in the way.

For centuries, charting the murky depths meant braving the high seas, dangling plumb lines over the side of a ship, then drawing basic contours on cartographic maps. Sailors etched soundings onto maps as early as the 16th Century, but no international standards for terminology or scale existed then, meaning early maps were not only rudimentary wayfaring tools, they were also confusing and contradictory.

It wasn’t until the turn of the 20th Century, an era marked by soaring interest in the natural world, that a group of geographers gathered under the leadership of Prince Albert I of Monaco to produce the first international charts of the ocean (what would eventually become Gebco). Albert was fascinated by the then relatively new science of oceanography, and commissioned four research yachts to survey the Mediterranean. More than 100 years later, Gebco and the Nippon Foundation formally announced Seabed 2030, a project that aims to map the entire sea floor by the year 2030 using data gathered from vessels around the world – including soundings from those early expeditions.