In an event unable to be understood at the time, a pinpoint black hole struck the Earth near the Stony Tunguska River in Siberia, Russia. The impact itself was significant with a shockwave estimated at 5.0 on the Richter scale that knocked trees flat in an 800 square mile spread, blew people off their feet, and destroyed windows for hundreds of miles. The aftershock, however, was far more important. As the black hole bore through the Earth, it shed the event-horizon shell of cosmic matter and evaporated with the energy from friction and pressure of the Earth's core. The shockwaves continued through the molten core and mantle like an isolated earthquake, meeting on the opposite side of the world near the Strait of Magellan. There, the edge of the Antarctic Plate buckled with the South American Plate, causing a massive upheaval that would turn the Drake Passage into an enormous mountain range connecting the Andes and the Antarctic Peninsula.
At the time, however, the world's attention was turned to the new landmass that had suddenly cut off the Atlantic and Pacific Oceans (what would later be termed as the “exit wound” of the black hole, though it was really only backlash from the collision). As ocean currents adjusted, climatological alterations began such as the increase of rainforest to the south of the Amazon and the widening of the Kalahari Desert. Sea life suffered greatly as migration routes were cut off, causing the extinction of several whale species, already over-hunted. Most notable to the time was that the most-used passage to the Pacific had been cut off. Since its discovery by Balboa, the Pacific had struck Europe as a new, calmer ocean for exploration and colonization. The Pacific had been especially instrumental to the Americans, who used it as the main route connecting them to the quickly populated West Coast even after the construction of the Transcontinental Railroad. A faster route was currently under construction through a canal in Panama, but at the time of the Upheaval, it was still years from completion. The long-sought Northwest Passage had only recently been completed by Roald Amundsen from 1903 to 1906 and could be crossed only at the warmest points of summer by reinforced icebreaker ships.
Effectively, the Pacific had become cut off from the East. Shipping could still flow through the Indian Ocean, but the journey from New York to San Francisco by steamer had increased from weeks to months. Calling the times “desperate,” US President Theodore Roosevelt began his campaign for his unprecedented third term and vowed not to leave office until his canal was completed (which occurred years before schedule in 1911). The rest of the world looked with shock and envy at America controlling the only access to the eastern Pacific, and soon multiple European-backed companies began plans to dig canals through Honduras, Costa Rica, and, especially, Nicaragua. Only the Nicaraguan Canal would see completion in 1923, after changing hands twice.
Other plans, however, determined that overland routes would be suitable. On February 12, 1908, the New York to Paris Race began, traveling by motor car and partially by steamer west from Times Square to the French capital. A month after the Upheaval, the American team arrived victorious in their Thompson Flyer. Savvy newspapermen used the event as an example of the efficiency of overland travel. The Germans (whose team arrived second), took notice of the feat and began work with the ABC Powers (Argentina, Brazil, and Chile) to complete a rail and motorway that would bring goods from Buenos Aires to Santiago. German imperial attention turned to South America, bringing commerce and tourism, so much so that commentators doubted the Kaiser had even noticed the short-lived Austrian occupation of Serbia.
Gradually, the world would become accustomed to its new scar of what came to be known as the Drake Mountains, but the idea that an object from space could bring such devastation to a planet continues to unnerve the human spirit.
In reality, the mysterious Tunguska blast was most likely an air burst of a meteoroid. It produced an explosion that would not be rivaled by man until atomic weapon tests of the 1950s. Other hypotheses about the explosion have labeled it the activity of antimatter, aliens, Nikola Tesla, or, famously in 1973, University of Texas physicists Albert Jackson and Michael Ryan suggesting the idea of a small black hole (though it would not have left the telltale minerals found in later expeditions).
More info on Tunguska at Matt's Today in History blog. http://mattstodayinhistory.blogspot.com/2011/06/tunguska-event-june-30-1908.html