Sound is a traveling wave which is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations. Audio: Takeshi Sato / NewsTimes

Iona shoe polisher. The makers of 'Ghostbusters' cannibalized one of these for the assembly of a prop handheld 'ghost detector.' Photo: Janey Crane / AP
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The Golden Age of Trucking Museum in Middlebury is a good place to enjoy some vintage trucks. Bring the kids and enjoy the antique ambiance. The museum has been greeting about 20,000 visitors a year since opening its doors in 2002. Along with trucks by manufacturers like Mack and the now-defunct Diamond T there are army vehicles, dairy vans and much more. Video: Tony Spinelli / CT Post

Tourists can walk amid Armand Vaillancourt's sculpture "Québec libre!" This fountain can be found at the Embarcadero Center in San Francisco, California. Photo: Dorothea Chaplet / Huron Daily Tribune
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The objective is to race through the Mushroom Kingdom, survive Bowser's forces and save Princess Toadstool. The game consists of eight worlds with four sub-levels in each world. Interactive: Guillame Pouetpu / Seattle P-I

'Naka' is Japanese for 'inside.' 'Kasa no naka' means 'under an umbrella.' The term parasol usually refers to an item designed to protect from the sun, and umbrella refers to a device more suited to protect from rain. Photo: Susan Foreman / Edwardsville Intelligencer
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The Moller SkyCar at the Wired NextFest. In a model proposed for the general public, the driver would only input direction and speed. Piloting knowledge would be unnecessary. Photo: Mel Bush / SF Chronicle
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Seattle-Tacoma Airport was constructed by the Port of Seattle in 1944 to serve civilians of the region, after the U.S. military took control of Boeing Field for use in World War II. Photo: Vislor Turlough / Stamford Advocate
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Washington state intended to run the Puget ferry service only until cross-sound bridges could be built, but these were never approved and the Department of Transportation runs the system to this day. Photo: Zoe Herriot / Midland Daily News
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Richard Branson & Nik Powell had initially run a small record shop called Virgin Records and Tapes on Notting Hill Gate, London, specialising particularly in 'krautrock' imports. Photo: Romana Trelundar / Midland R-T
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The name Virgin, according to Branson, arose from a colleague of his when they were brainstorming business ideas. She suggested Virgin - as they were all new to business. Photo: Tegan Jovanka / Laredo Morning Times
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The presence of the Houston Chronicle building and Jesse Jones Hall were accounted for in wind tunnel-based estimates of cladding pressures. Photo: Harry Sullivan / SF Chronicle
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Disused Goss printing presses at the rear of the Houston Chronicle building. The Goss Printing Company, founded in Chicago in 1885, was the first company to combine multiple high-speed rotary presses into a single machine that could print entire newspapers in one press run. Photo: Ian Chesterton / Houston Chronicle
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Disused Goss printing presses at the rear of the Houston Chronicle building. The Goss Printing Company, founded in Chicago in 1885, was the first company to combine multiple high-speed rotary presses into a single machine that could print entire newspapers in one press run. Photo: Ian Chesterton / Houston Chronicle
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Disused Goss printing presses at the rear of the Houston Chronicle building. The Goss Printing Company, founded in Chicago in 1885, was the first company to combine multiple high-speed rotary presses into a single machine that could print entire newspapers in one press run. Photo: Ian Chesterton / Houston Chronicle
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LTI 'black cab' in San Francisco. North American buyers of LTI taxis have to pay for them in pound sterling, which means converting their dollars into UK currency. Photo: Steven Taylor / Houston Chronicle
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Public Storage built its first self-storage facility in 1972. Today it operates over 2,100 company-owned locations in the United States and Europe (under the Shurgard brand name). Photo: Barbara Wright / SF Chronicle
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Houston is home to Merit Parking's corporate office and is the city where Merit got its start. Photo: Peri Brown / Edwardsville Intelligencer
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BART tracks, San Francisco International Airport. BART connects with AirTrain, a fully automated people mover that operates 24 hours every day. Photo: Victoria Waterfield / Greenwich Time
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Cola was invented by the druggist John Pemberton. Brocade is a class of richly decorative shuttle-woven fabrics, often made in colored silks. Photo: Jo Grant / Houston Chronicle
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Cheerwine is a soft drink produced by the Carolina Beverage Corporation of Salisbury, North Carolina. It has been produced since 1917. Photo: Vicki Pallister / Midland Daily News
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Cole Hardware is a family-owned independent business with four locations in San Francisco, including the acquired Cole Fox Hardware on Third Street. Photo: Janey Crane / Times-Union
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The Civic Arts Commission awarded a contract to design and construct two gates for the city corporation yard to Eric Powell, a Berkeley artist. Photo: Mickey Smith / MySA
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