A 1914 photograph of the USS Santa Clara transiting through the Miraflores locks of the Panama Canal.
1914: The Panama Canal – A Marvel of Engineering and Geopolitics

The Panama Canal, completed in 1914, drastically reduced maritime travel time and remains one of the busiest shipping lanes in the world

September 2000 image displaying the largest recorded "ozone hole" above Antarctica, based on data captured by the Total Ozone Mapping Spectrometer (TOMS) instrument aboard the NASA Earth Probe satellite.
1913: The Discovery and Preservation of the Ozone Layer

The discovery of the ozone layer by Fabry and Buisson, and its monitoring by Dobson, led to crucial actions to reverse its depletion caused by CFCs

Main image: A 1930 photograph of German meteorologist and geologist Alfred Wegener. Inset: An early computer-assisted reconstruction of Pangea, fitting many of the current continents together.
1912: Alfred Wegener and the Theory of Continental Drift

Alfred Wegener's theory of continental drift, initially met with skepticism, fundamentally changed geology with the later discovery of tectonic plates

A 2012 photo of the ruins of the fifteenth-century Inca city Machu Picchu, now an archaeological site, in Peru.
1911: Machu Picchu – Rediscovery by Hiram Bingham

Hiram Bingham's discovery and restoration of Machu Picchu illuminated the historical significance of this Inca site, now a renowned Peruvian attraction

Photograph of Roald Amundsen (right) and three other members of his team planting the Norwegian flag at the South Pole on December 17, 1911.
1911: The Race to the South Pole – Amundsen vs. Scott

The early 20th-century race to the South Pole saw Roald Amundsen triumph over Robert Scott, marking a significant chapter in polar exploration history

Photograph of Wallace, Idaho, residents searching through the town's wreckage after the Great Fire of 1910.
1910: The Big Burn – America’s Largest Wildfire

The Big Burn of 1910, a historic and massive wildfire, shaped U.S. firefighting policies and highlighted the ecological significance of wildfires

Main image: A photograph taken in April 1909 by Robert Peary of his exploration team at what they believed to be the geographic North Pole. Inset: A photograph from 1909 showing Admiral Robert Peary dressed in full Arctic fur attire.
1909: Robert Peary’s Controversial North Pole Expedition

Robert Peary's 1909 claim of reaching the North Pole is surrounded by controversy and debate, representing a significant chapter in polar exploration history

Main image: An artistic interpretation by artist and planetary scientist William K. Hartmann depicting the Tunguska forest just one minute after the airburst explosion. The painting was created at Mount St. Helens, which experienced a blast similar to Tunguska in 1980. Inset: A 1927 photograph from the Kulik expedition to the Tunguska region.
1908: The Tunguska Event – A Meteoric Mystery in Siberia

The 1908 Tunguska explosion, a mysterious airburst in Siberia, underscores the impact of celestial objects on Earth and remains a pivotal study in planetary science

The largest known fragment of the small metallic asteroid responsible for creating Meteor Crater, showcased at the crater's visitor center in Winslow, Arizona.
1906: Daniel Barringer’s Quest for Meteorites – Unraveling Impact Crater Mysteries

Daniel Barringer's persistent efforts to uncover meteorite remnants in an Arizona crater significantly contributed to the understanding of impact cratering in geology

A photograph capturing the view down Sacramento Street, showing the wreckage and subsequent fire resulting from the San Francisco earthquake on April 18, 1906.
1906: The 1906 San Francisco Earthquake – A Seismic Event in History

The 1906 San Francisco Earthquake, a major seismic event, prompted significant advancements in building and urban planning, highlighting the impact of tectonic activities