Every huge block of stone (some of which weigh up to 6 tones) was carved to perfectly fit in its place, making this grandiose structure a marvel of masonry & engineering. A number of writers celebrated this bridge in their works, including Jean-Jacques Rousseau in “Confessions”. Numerous inscriptions, some ancient Roman in origin, cover the stones, making the whole site a historian’s and photographer’s paradise.

(images credit: candi)

2. Double Spiral Bridge in JapanThe Kawazu-Nanadaru Loop Bridge consists of two spirals, each 1.1 km long, 80-meter in diameter - the only way for traffic to get down the mountainside into the valley, too steep for any other usual road-building solutions. The busy Route 414 serves the weekend crowd from Tokyo, intent to wind down at the hot springs resort of the Izu Peninsula. The “winding down” bit obviously starts at this bridge. Built in 1981, the double-spiral structure demands careful driving - the speed limit on the bridge is only 30 km/h, which also helps to better enjoy the views.

(image credit: whatjamiefound)

(image credit: Toshiaki Iwahori)

Santiago Calatrava is one the most sought-after bridge architects today. His works are dynamic, reflecting our modern age. They also possess the uplifting harmony of sweeping curves and intricate shapes. His Sundial Bridge at Turtle Bay is an interestingly shaped, somewhat futuristic bridge (which doubles as a sun-dial). It was recently built near Redding, California.

(image credit: turtlebay.org)

(image credit: Bernadette Durbin)

Calatrava also applied his soaring, spread-wings style to the footbridge at Milwaukee Art Museum:

(images credit: Jim Brozek)

Although nothing really comes close to the City of Arts and Sciences that he designed for Valencia, Spain - the culmination of his highly elegant style.
Salvador del Saz has an awesome set of photographs of the building and the bridge leading to it:

(images credit: Salvador del Saz)

Also a bridge-tunnel combo, but smaller, is Merrimack/Monitor Memorial Bridge-Tunnel on Hampton-Chesapeake Interstate 664:

Similar spiral skyway graces the approach to the Nanpu Bridge over the Huangpu River, located at the South Dock in Shanghai, China. Drivers are allowed to go only clockwise… no, just kidding.

(original unknown)

The longest bridge in the world is oficially Lake Pontchartrain Causeway in Louisiana, which is essentially just a stretch of highway. The following structure is a bit more interesting:

6. The Bosphorus Bridge - connecting 2 continents

This grand-looking bridge spans the Bosphoruc Strait in Istanbul, Turkey. Interestingly, it also has a twin: a similar bridge located just down the Strait.

7. The Hanging Bridge of Bilbao, Spain

Built in 19th century, in a year of 1893, it introduced truly revolutionary combination of 150-meter long steel bridge and a hanging gondola, moving across the river. Similar structures were built after its example, but only a few remain in existence today in the world. The 43-meter towers present an imposing view over the city:

Another interesting bridge concept: a footbridge with counter-balancing weights:

(image credit: Kiel Bryant)

The “bridge-to-nowhere” illusion, seen in Norway:

(image credit: ochevidec)

A few other interesting (and beautiful) bridges:

Stonebridge in Regensburg, Germany:

(image credit: Luca Ivaldi)

Freedom Bridge, Budapest, Hungary:

JK bridge across Paranoa Lake, in Brazil:

Newport Pell Bridge, Newport, Rhode Island:

Conwy Suspension Bridge in the medieval town of Conwy, North Wales:

The Tsing Ma Bridge, Hong Kong:

Strange bridge in Victoria, Canada: Johnson Street Bridge.

(image credit: letmestayforaday)

Spiral bridge-link between two buildings, over Floral Street in London:

And our traditional mystery bridge:

UPDATE: Colsh says: “The mystery bridge is the Skye bridge connecting the Isle of Skye to mainland Scotland. I believe at one time the most expensive toll bridge in the world (per kilometer).”