• 1800 - 1900 | 1900 - 1950 | 1950 - 1975 | 1975 - 2012

    1807 U.S. Coast Survey
    President Thomas Jefferson signs a bill authorizing the United States Coast Survey.
    1842 Coral Atolls Explained
    Charles Darwin publishes a paper suggesting that coral atolls are the final stage in the subsidence and erosion of volcanic islands.
    1857 Undersea Canyons
    James Alden discovers the first known submarine valley, California's Monterey Canyon.
    1868 Life in the Deep Sea
    Charles Wyville Thomson, dredging from the H.M.S Lightning, finds sea life at 4,389 meters (14,400 feet), shattering previous theories that the sea was lifeless below 549 meters (1,800 feet).
    1872 Early Marine Survey of the Americas
    Naturalist Louis Agassiz steams from the U.S. East Coast to its West Coast around South America, collecting some 30,000 marine specimens.
    1872-76 Marine Research and Oceanography
    H.M.S. Challenger circles the globe conducting reseach for the Royal Society of London, laying the groundwork for modern oceanography.
    1882 The First Oceanographic Research Vessel
    The U.S. Fisheries Commission steamer Albatross begins operations\u2014the first ship built to serve as an oceanographic research vessel.
    1899-1905 Marine Survey of the South Pacific
    Alexander Agassiz makes long research voyages to the South Pacific, collecting data and specimens from remote ocean regions.

    1912 The Sinking of the Titanic
    The Titanic sinks after hitting an iceberg, killing 1,500 people. The tragedy led to efforts to develop an acoustic device to find objects ahead of a vessel.
    1914 First Acoustic Exploration of the Seas
    Reginald Fessenden uses an oscillator to bounce a signal simultaneously off an iceberg and the seafloor\u2014first acoustic exploration of the seas.
    1925 Studying the Mid-Atlantic Ridge
    The German Meteor expedition surveys the South Atlantic with echo sounders, proving the continuity of the Mid-Atlantic Ridge.
    1934 The Bathysphere
    William Beebe is lowered in a tethered bathysphere to 923 meters (3,028 feet). He and partner Otis Barton pioneered manned exploration of the ocean.
    1943 The Creation of the Aqua-Lung
    Jacques Cousteau and \u00c9mile Gagnan modify a demand breathing regulator to engineer the Aqua-Lung\u2014forever changing the course of human interaction with the sea.

    1954 An Untethered Submersible Dive
    The French research submersible FNRS-3 descends to 4,041 meters (13,257 feet) off the coast of West Africa, piloted by Georges Houot and Pierre Willm, inaugurating use of manned, untethered, research submersibles.
    1955 Discovery of Magnetic Striping on Ocean Floor
    The U.S. Coast and Geodetic Survey ship Pioneer, in a joint project with the U.S. Navy and the Scripps Institution of Oceanography, tows the first marine magnetometer and finds magnetic striping on the seafloor off the West Coast. The discovery adds a key element to the theory of plate tectonics.
    1960 The Trieste Explores the Mariana Trench
    The bathyscaphe Trieste dives to what was believed to be the deepest point in the Mariana Trench, recording a depth of 10,912 meters (35,800 feet). Exploring the same area in 1998, a Japanese research vessel measured a depth of 10,938 meters (35,886 feet).
    1961 Development of the Deep Tow System
    The Scripps Institution of Oceanography begins development of the Deep Tow System, the forerunner of all remotely operated unmanned oceanographic systems.
    1964 Submersible Deep Dives
    The Deep Submergence Vehicle Alvin is constructed by the Woods Hole Oceanographic Institute. Alvin was the first U.S.-based deep-diving submersible, and has now made over 4,400 descents and led to numerous ocean floor discoveries.
    1965 An Underwater Lab
    Sealab II, an underwater habitat, is lowered off the coast of California.
    1970 Sylvia Earle Leads Women Aquanauts
    Sylvia Earle leads the first team of women aquanauts during the Tektite Project and sets a record for solo diving to a depth of 1,000 meters.

    1977 Robert Ballard's Discovery of Hydrothermal Vents
    Hydrothermal vents are discovered, along with an ecosystem that survives without the energy of the sun, by a team led by Robert Ballard. These ecosystems rely on biota absorbing chemical energy from the venting materials in a process called chemosynthesis.
    1985 The Discovery of the Sunken Titanic
    A research team lead by Robert Ballard discovers the Titanic more than 3,810 meters (12,500 feet) down, the most famous shipwreck in modern history.
    1992 Creating Sea Surface Maps
    TOPEX/Poseidon satellite begins mapping the surface of the sea.
    1995 Creating Seafloor Maps
    Declassification of GEOSAT radar altimetry data from a U.S. Navy Earth observation satellite leads to worldwide mapping of the seafloor.
    2010 Cataloging the Biodiversity of the Ocean
    The first ever Census of Marine Life catalogs the diversity, abundance, and distribution of marine species collected in an online database.
    2012 First Successful Solo Dive to the Mariana Trench
    National Geographic Explorer-in-Residence James Cameron successfully travels to the bottom of the deepest known point in the ocean, Challenger Deep, in the Mariana Trench on the DEEPSEA CHALLENGE expedition. DEEPSEA CHALLENGE is a joint scientific project by James Cameron, the National Geographic Society, and Rolex. This is the first time someone has traveled to this depth since 1960, when the Trieste made its descent, and the first time it has ever been done as a solo mission.