The Vashon Glacier, a sheet of ice once 3,000 feet deep at its thickest, retreats northward. It leaves a deep canyon, now known as Puget Sound, in its wake.

The oldest recorded archaeological site in the Puget Sound area is the Manis Mastodon site near Sequim, more than 12,000 years old. Did Native Americans come to the New World by walking across the Bering Land Bridge? Did they make their way along the coast in watercraft? Or have they been here since the dawn of time?

Mount Rainier erupts, sending massive mudflows down the White River and Duwamish River drainages. The sediment from the eruption - the Osceola Mudflow - will slowly build up where the Duwamish enters Puget Sound. Over the next 4,500 years, the shoreline will move from near Auburn to the SoDo area of Seattle.

The discovery of stone tools shows that the West Point site adjacent to Discovery Park in north Seattle was occupied around 4,000 years ago, and visited centuries earlier. Closer to downtown Seattle, a large village on the Duwamish River was occupied several times between AD 670 and 1700. The Duwamish people hunted, gathered wild plant materials, and fished for abundant salmon and other seafood. The Duwamish and neighboring tribes continue to live in the Seattle area.

European explorers begin naming - and claiming - parts of Puget Sound. In 1775, the Spanish ship Santiago makes the first recorded landing in Washington at Point Grenville on the Pacific coast.

In 1792 Captain George Vancouver of the British Navy conducts the first European survey of Puget Sound. His expedition names many of the area's bays, islands and mountains, including Mount Rainier and Puget Sound itself.

Lieutenant Charles Wilkes begins the first American survey of Puget Sound, producing the earliest detailed map of what would become the Seattle area.

The Denny party settled at Alki Point in 1851, but most relocate to Denny Island in what is now Pioneer Square in 1852 after a harsh winter on the exposed point.

Seattle grows slowly into a thriving city of 40,000, but much of it burns to the ground in the Great Fire of June 6, ignited in a cabinet shop. Buildings are quickly re-built of brick, in the latest architectural styles. Shortly afterward, voters approve purchase of the Cedar River watershed and the construction of a modern water system.

The first automobile arrives in Seattle on July 23, only 16 years after the first streetcar line begins. Interurban rail service to Tacoma debuts two years later, but does not extend to Everett until 1910.

The Great Northern Railway completes a tunnel beneath downtown Seattle, taking many trains off the waterfront. Soon afterward, two grand terminals are completed - King Street Station (1906) and Union Station (1911).

On August 17, farmers begin selling their produce on Pike Place. Fed up with the high mark-ups charged by wholesalers, hundreds of shoppers overwhelm the farmers. Soon, more than 120 farmers have stalls at the Pike Place Market.

On June 1, the Alaska-Yukon-Pacific Exposition opens and more than a million visitors enjoy its varied entertainments and international exhibits before it closes in October. The fairgrounds, on the University of Washington campus, are designed by the Olmsted Brothers, whose parks and boulevards plan influences city planning for more than a century. Their second plan, in 1909, includes the six towns incorporated into the city in 1907, doubling Seattle's size.

On May 19, the gangplank collapses on the steamer SS Flyer at Colman Dock (Pier 52). The vessel was one of the dozens of Mosquito Fleet steamboats that connected ports throughout Puget Sound into the 1930s. In the 1940s, they were replaced by car ferries. As fares rise rapidly, the state purchases the private ferry monopoly and the Washington State Ferries begin service on June 1, 1951.

The city completes the last of three phases of the Denny regrade. The regrade removed Denny Hill, which once stood between First and Westlake avenues, and Pike and Harrison streets. Spearheaded by City Engineer R. H. Thomson, dozens of hills were regraded from the 1890s to the 1930s in an effort to make Seattle easier to traverse. Workers removed sediments by steam shovel or hydraulic dredge, and dumped in Elliott Bay or wherever fill was needed.

The Great Depression hits Seattle hard, and the unemployed create "Hooverville," a community of makeshift shacks at an abandoned shipyard near S. Dearborn Street. New Deal public works programs complete major projects such as the Elliott Bay Seawall and the Aurora Bridge. At the end of the decade, the looming war in Europe brings work for everyone.

The Battery Street Tunnel opens on July 24, at last providing a direct link from the "speedway" on Aurora Avenue to the Alaskan Way Viaduct. The first section of the viaduct (from Battery Street to S. Dearborn Street) had opened in April 1953.

In 1959 the Alaskan Way Viaduct was extended to S. Holgate Street where it ran into E. Marginal Way S. and on toward Tacoma. Construction of the downtown ramps was delayed until funding was available, with the Seneca Street off-ramp opening in 1961 and the Columbia Street on-ramp five years later. More information on the history of the Alaskan Way Viaduct in Seattle can be found on the History page.

The Century 21 World's Fair focused on visions of the future, began its 6-month run on April 21. More than 10 million visitors (including Elvis Presley, Prince Philip and astronaut John Glenn) enjoyed the entertainment, cultural events and exhibits from 59 countries. The Space Needle, Monorail, Pacific Science Center and much of the Seattle Center remain today from the fair.

City officials apply for Pioneer Square to become one of the nation's first historic districts, saving it from re-development. Private and public funding rehabilitates Seattle's oldest buildings and adds improvements such as parks and street trees. In 1971, voters approved an initiative to preserve and restore the Pike Place Market, which had also been threatened with demolition, and it became a historic district soon after.

The Mariners begin playing in their new baseball stadium adjoining Pioneer Square. It is joined in 2002 by a new stadium for the Seahawks. However, to make room for it, the Kingdome, an enclosed stadium built in 1972, is imploded.

The 6.8 magnitude Nisqually earthquake struck Seattle on February 28, damaging the Alaskan Way Viaduct and many buildings in Pioneer Square and SoDo. But it was not as powerful as the 7.1 magnitude quake in 1949, the largest in Seattle's recorded history. It killed eight people, injured dozens and caused extensive damage.