1869 John Wesley Powell's first expedition


1908 President Theodore Roosevelt makes Grand Canyon a national monument.


1911-12 Emery and Ellsworth Kolb make a movie of a river trip.


1919 Grand Canyon becomes a national park. First airplane overflight.


1922 Phantom Ranch is built.


1935-36 Hoover Dam is completed and Lake Mead National Recrea-tion Area established.


1937 Buzz Holmstrom makes the first solo trip.


1938 Amos Burg runs first inflatable boat. Norman Nevills (with Elzada Clover & Lois Jotter) runs first commercial trip.


1948 Fewer than 100 people have traversed the Canyon.


1955 John Daggett and Bill Beer swim the Colorado River from Lees Ferry to Lake Mead.


1956 Congress authorizes construction of Glen Canyon Dam.


1964 Glen Canyon Dam begins producing electricity. 900 people have run the river.


1972 Almost 16,500 run the river in one year.


1973 Park Service freezes commercial and private river use at 1972 levels.


1980-81 Lake Powell fills after 17 years.


1997 Almost 25,000 run the river.


* Adapted from The Colorado River in Grand Canyon: a guide, by Larry Stevens, published by Red Lake Books, Flagstaff, Ariz.