The provided text, "Ocean's Unknown Deep Frontier," offers a comprehensive overview of deep-ocean exploration, highlighting the vast, undiscovered nature of our planet's underwater realms despite significant advancements in mapping technology. It details the cutting-edge sonar systems and robotic vehicles that enable scientific investigation, revealing extraordinary ecosystems like hydrothermal vents and the hadal zone where life thrives under extreme conditions, as well as unique brine pools. The source also examines the ocean's role as a geological force and an archive of both natural phenomena and human history, from ancient landmasses to shipwrecks. Finally, it contrasts the underfunding of ocean exploration compared to space exploration, emphasizing its critical importance for medicine, climate regulation, and understanding life, while raising concerns about the growing threat of deep-sea mining.