Road Trip Pic of the Day challenge -- 63 days of mystery (pictures)

The June 12 challenge -- which 70 people got -- was the western underside of the northern approach to the Golden Gate Bridge.

The June 13 challenge -- which 146 people got -- was the Zeiss refracting telescope in the east dome of the Griffith Observatory, in Griffith Park, Los Angeles.

The June 14 challenge -- which 307 people got right -- was the existing and currently under construction eastern spans of the Oakland-San Francisco Bay Bridge.

The June 15 challenge -- which 788 people got right -- was the former federal prison (and now, tourist attraction) Alcatraz, located in the San Francisco Bay.

The June 16 challenge -- which 21 people got right -- was the Gravity Car Barn (part of the old Mount Tamalpais & Muir Woods Railway) near the East Peak (and the fire lookout at the top of the East Peak) of Mount Tamalpais in Marin County, Calif.

The June 17 challenge -- which 78 people got right -- was a United Airlines DC-8, located outside the California Science Center at Exposition Park in Los Angeles.

The June 18 challenge -- which 62 people got right -- was Death Guild's Thunderdome at Burning Man in the Black Rock Desert of Nevada.

The June 19 challenge -- which 208 people got -- was the Pigeon Point Lighthouse and Hostel, in Pescadero, Calif.

The June 20 challenge -- which 112 people got right -- was the Moss Landing Power Plant in Moss Landing, Calif.

The June 21 challenge -- which 82 people got right -- was the The Caboose (Books, Bears, and Railroad Wares) in Cannery Row, Monterey, Calif.

The June 22 challenge -- which 220 people got -- was the Monterey Bay Aquarium, in Monterey, Calif.

The June 23 challenge -- which 57 people got right -- was the Pillar Point Air Force Station, in Half Moon Bay, Calif.

The June 24 challenge -- which 27 people got right -- was the view from the road leading to Hearst Castle, in San Simeon, Calif., with Hearst's old private airfield visible in the background.

The June 25 challenge -- which 94 people got right -- was Keenan's Cambria Village Pharmacy, in Cambria, Calif.

The June 26 challenge -- which 196 people got right -- was the Bixby Creek Bridge, located in Big Sur, Calif.

The June 27 challenge -- which 98 people got right -- was McWay Falls in Julia Pfeiffer Burns State Park in Big Sur, Calif.

The June 28 challenge -- which 66 people got right -- was the El Bordello Alexandra, a former brothel turned apartment building in Venice, Calif.

The June 29 challenge -- which 27 people got right -- was the Chalon campus of Mount Saint Mary's College in Los Angeles.

The June 30 challenge -- which 123 people got right -- was artist Jonathan Borofsky's "Ballerina Clown," mounted on the Venice Renaissance Building in Venice, Calif.

The July 1 challenge -- which 68 people got right -- was the Museum entrance hall at the J. Paul Getty Center in Los Angeles.

The July 2 challenge -- which 23 people got right -- was the under-construction Rain Rocks Rock Shed, alongside the Pitkins Curve Bridge, in Big Sur, just north of Limekiln State Park.

The July 3 challenge -- which 14 people got -- was the Academy of Motion Picture Arts and Sciences' Pickford Center for Motion Picture Study (home of the Academy Film Archive), in Hollywood, Calif.

The July 4 challenge -- which 52 people got right -- was the Spreckles Sugar Plant in Brawley, Calif.

The July 5 challenge -- which 17 people got right -- was Abengoa Solar's Solana solar power plant, a 280-megawatt parabolic trough plant currently under construction in Gila Bend, Ariz., that may end up as the world's largest such facility.

The July 6 challenge -- which 152 people got right -- was Kitt Peak National Observatory, near Tucson, Ariz.

The July 7 challenge -- which 53 people got right -- was the Old Trails Arch Bridge, as well as other pipeline bridges that span the Colorado River (and the border between Arizona and California) between Needles, Calif., and Topock, Ariz.

The July 8 challenge -- which 184 people got right -- was London Bridge, in Lake Havasu City, Ariz.

The July 9 challenge -- which 133 people got right -- was the Coca-Cola bottling plant in Los Angeles.

The July 10 challenge -- which 75 people got right -- was the old one-room schoolhouse in San Simeon, Calif., that was once used by children of Hearst Castle ranchhands. Hearst Castle is visible at the top of the hill in the background.

The July 11 challenge -- which 120 people got right -- was the Piedras Blancas Light Station, north of San Simeon, Calif.

The July 12 challenge -- which 120 people got right -- was Dynegy's Morro Bay Energy Facility, in Morro Bay, Calif.

The July 13 challenge -- which 60 people got right -- was the Hollywood Reservoir, also known as Lake Hollywood, and the Mullholland Dam, in the Hollywood Hills of Los Angeles.

The July 14 challenge -- which 53 people got right -- was the Space Age Lodge and Restaurant, in Gila Bend, Ariz.

The July 15 challenge -- which 25 people got right -- was Broken Hill, at Torrey Pines State Natural Reserve in San Diego.

The July 16 challenge -- which 79 people got right -- is the Ramon C. Cortines School of Visual and Performing Arts, formerly known as Central Los Angeles Area New High School No. 9, in Los Angeles.

The July 17 challenge -- which 140 people got right -- was artist Do Ho Suh's "Fallen Star," a small Rhode Island-style cottage hanging off the top of the Jacobs Engineering Building at the University of California at San Diego.

The July 18 challenge -- which 194 people got right -- was Hemenway Harbor at Lake Mead in Nevada.

The July 19 challenge -- which 83 people got right -- was the Del Mark Racetrack, in Del Mar, Calif.

The July 20 challenge -- which 57 people got right -- was the Chateau Marmont, in West Hollywood, Calif.

The July 21 challenge -- which 24 people got right -- was a set of hanging kites decorating The Crystals, or Crystals at CityCenter, in Las Vegas, Nev.

The July 22 challenge -- which 137 people got right -- was the Mike O'Callaghan-Pat Tillman Memorial Bridge (also known as the Hoover Dam Bypass Bridge) on U.S. Route 93 near Boulder City, Nev.

The July 23 challenge -- which 75 people got right -- was part of Caltech's Owens Valley Radio Observatory, located outside of Big Pine, Calif.

The July 24 challenge -- which nine people got right -- was the Railtown 1897 State Historic Park, in Jamestown, Calif.

The July 25 challenge -- which 161 people got right -- was artist Tim Hawkinson's sculpture, "Bear," located on the campus of the University of California at San Diego.

The July 26 challenge -- which 138 people got right -- was the Venice Beach Handball Courts, in Venice, Calif.

The July 27 challenge -- which 91 people got right -- was a tunnel on Big Oak Flat Road in Yosemite National Park.

The July 28 challenge -- which 138 people got right -- is the San Diego-Coronado Bridge, connecting San Diego and Coronado, Calif.

The July 29 challenge -- which 358 people got right -- was the Mormon Temple in San Diego, Calif.

The July 30 challenge -- which 151 people got right -- was the Geisel Library (named for Dr. Seuss, aka Theodor Geisel) at the University of California at San Diego, in La Jolla, Calif.

The July 31 challenge -- which 233 people got right -- was the San Onofre Nuclear Generating Station in Pendleton, Calif.

The August 1 challenge -- which 58 people got right -- was the Mark Twain Cabin, a replica of the cabin in which the author worked on "The Jumping Frog of Calaveras County," on Jackass Hill near Tuttletown, Calif.

The August 2 challenge -- which 21 people got right -- was the "Green Church," located at the intersection of U.S. Highway 395 and Benton Crossing Road, near Mammoth Lakes, Calif.

The August 3 challenge -- which 71 people got right -- was the Historic Railroad Tunnel Trail at the Lake Mead National Recreation Area near Boulder City, Nev., and Hoover Dam.

The August 4 challenge -- which 62 people got right -- was the Frog statue in Angels Camp, Calif., the locale of Mark Twain's short story "The Celebrated Jumping Frog of Calaveras County."

The August 5 challenge -- which 39 people got right -- was "Treehouse," by architect Frank Gehry, in Venice, Calif.

The August 6 challenge -- which three people got right -- was a backdrop in the Cirque du Soleil show, "Iris," located in Los Angeles, Calif.

The August 7 challenge -- which 52 people got right -- was the Immaculate Conception Church, in Ajo, Ariz.

The August 8 challenge -- which 167 people got right -- was Morro Rock, in Morro Bay, Calif.

The August 9 challenge -- which 11 people got right -- was presumptive Republican party presidential nominee Mitt Romney's house in La Jolla, Calif.

The August 10 challenge -- which 33 people got right -- was the former Boron Air Force Station, north of Kramer Junction, Calif.

The August 11 challenge -- which 154 people got right -- was the Walt Disney Concert Hall, in Los Angeles, Calif.

The August 12 challenge -- which 45 people got right -- was Walt Disney Studios and Walt Disney Animation, in Burbank, Calif.