Before you kick the pigeon lusting after your lunch, bear in mind that the bird could be a descendant of one of the early pioneers of modern aerial photography. Around 1908, several pigeons carrying specially designed automatic miniature cameras flew over a castle in Kronberg, Germany, photographing as they flapped.

"Looking at Earth," a new exhibit at the National Air and Space Museum, celebrates the development of aerial and orbital photography over the past 100 years. It took 2 1/2 years to put together and draws on the museum's own collection of airplanes, satellites and other hardware as well as photographs from the CIA and other government agencies.

"We wanted to update our satellite exhibit and expand it to show the practical applications of aerial and orbital photography," says curator Priscilla Strain. "We've included photographs from the 19th century as well as the newest photos from space."

Alongside the humorous pigeon photograph is a very serious letter from President Lincoln to Gen. Winfield Scott, encouraging Scott to meet with balloonist Thaddeus Lowe. Lincoln believed balloons should be incorporated into Army operations, but Scott was skeptical. Eventually, Lincoln's suggestion was adopted, and as late as the 1950s the Army used balloons to provide photo reconnaissance of the Soviet Union, as part of its "Moby Dick" program.

While the documentation of the early days of aerial photography is fascinating, the U2 spy plane is the star attraction. Produced in the 1950s by Lockheed, the U2 was the first aircraft that could fly at high altitudes without being detected. That was until 1960, when pilot Francis Gary Powers was shot down over Soviet airspace. Most likely Powers had a U2 survival kit with him, which included a machete and shark repellent, though in this instance it probably didn't help him much. Powers was later released and the U2 went on to photograph the Soviet missile buildup in Cuba, verify nuclear testing in China, perform photo reconnaissance in Vietnam and the Middle East and provide civilian disaster assessment.

Almost too big for the space in which it hangs -- part of the ceiling had to be knocked out to squeeze it in -- the once top-secret U2 is on public display at the center of the gallery.

Airplanes and satellites also allow us to monitor the weather, observe changes in terrain and the environment over time, study the oceans and do better city planning. And gallery organizers have done an excellent job translating complicated technology into plain English.

Landsat, for example -- the satellite carrying sensors and scanners that observe the Earth's surface -- is brought down to earth by a special display allowing visitors to view Landsat images of their home state. And weatherman Willard Scott in his folksy way explains the history of the weather satellite program in a short video that demonstrates how the satellites predict hurricanes and tornadoes.

Some of the aerial and satellite photos are spectacularly beautiful, particularly the Landsat images that depict Hawaii as a swirl of blue, red, aqua and green and the Grand Canyon as a collage of brown, gold and black. To scientists, these images describe geologic formations and the amount of vegetation in an area. To the untrained observer, they remind us how beautiful our planet is.

And that is clearly a major point of "Looking at Earth" and its companion art exhibition upstairs, "Earth Views" -- a collection of 89 works in various media inspired by viewing Earth from above.