No, you’re not seeing triple – these are Pittsburgh’s Three Sisters, a trio of nearly identical suspension bridges erected side by side over the Allegheny River.

Rachel Carson (Ninth Street Bridge)

All three were built between 1924 and 1928 by the aptly-named American Bridge Company, and they are the only trio of nearly identical bridges, as well as the first self-anchored suspension span bridges in the United States.

Andy Warhol (Seventh Street Bridge)

The 9th and 7th street bridges are named for Pittsburgh natives Rachel Carson and Andy Warhol, whilst the 6th is named for the baseball player Roberto Clemente, who played for the Pittsburgh Pirates, whose home field is the nearby PNC Park baseball stadium.

Roberto Clemente (Sixth Street Bridge)

Thanks to Google’s Street View feature, as well as being able to see what these bridges look like when you’re on them, we can also see what it’s like to cross the 6th street bridge and see the other two.

Thanks to Nitehawk. Read more about the Three Sisters at Wikipedia.

See our previous posts Double Bridge Shadow, Double Drawbridge and Three Sisters, Australia.

Last Sunday saw the swearing in of Boris Johnson, conservative MP for Henley (and renowned committer of gaffes), as the new Mayor of London. This means that, not only will he have power over nearly everything in Greater London, he will also take up office in London’s rather spectacular City Hall.

Opened in 2002, the glass clad building contains a 500 metre helical walkway, which eventually reaches ‘London’s Living Room’, a large space 10 floors up which affords rather spectacular views over the River Thames, and which also played host to Boris’ acceptance speech at the weekend (and unsurprising trip-up beforehand!).

Perhaps the new Mayor will be more accepting of the Norman Foster design than Ken Livingstone, who famously likened the building to a ‘glass testicle’. Boris however is said to refer to it as ‘The Onion’ – which fits, since the nearby ‘Gherkin’ is another work by Foster and Partners.¹

Here’s a link to the Live Maps Bird’s Eye view of London City Hall which really demonstrates the tower’s bizarre shape, or you can see lots of pictures and read more about it at GreatBuildings and wikipedia. Thanks to Krusader.

Lollapalooza is a multi-genre Music festival held each year in Chicago’s downtown Grant Park. The 3-day event draws over 35,000 people each day, and for the 2007 festival the special guest was you, the GSS readers.

We’ll start at the entrance, which is marked with large inflated letters that you can just about read from the aerial shot (ground level pictures). Don’t worry about paying though – we’re Access All Areas!

Let’s head south of the entrance, past these pretty star shaped balloons (ground level picture).

Continue south and we arrive at the “AT&T stage“, which played host to the likes of Daft Punk and Lupe Fiasco¹.

If Daft Punk aren’t your bag then let’s go all the way north (past the previously featured Clarence Buckingham Fountain) to the “Bud Light Stage“, where there’s currently a larger turn out. This stage featured The Roots, Snow Patrol and Amy Winehouse, amongst others.

You can explore Lollapalooza 2007 further with a kml image overlay I’ve created from the official festival map, and complete the festival experience by watching some of the acts on Youtube.

Thanks to Steve H.

This is the Aqueduct of Segovia, which was probably built during the second half of the 1st Century AD, and is one of the most significant and best-preserved Roman monuments in Spain.

Technically, this is just the bridge part of a much longer aqueduct which carries water to Segovia from 17 kilometres away. It is only when the aqueduct crosses Segovia’s Plaza Azoguejo that it really becomes a sight to behold. This ancient engineering masterpiece is comprised of 167 arches reaching up to 28.5 metres!

Some of the height is obvious in the Google Image thanks to the fantastic shadow, but here’s some ground level photos that give you a good sense of scale, and here’s another that conveys how incredibly old this structure is.

Thanks to Ignacio Sanz.

Connecting the Danish islands of Zealand and Funen is the Great Belt Fixed Link, another example of a confusing bridge / tunnel mash-up¹.

Starting on Funen at the Western end we have a 6611m bridge that carries both road and rail.

This bridge then abruptly ends at the tiny island of Sprogø, the site of a former prison used for women deemed “pathologically promiscuous”! During the bridge’s construction Sprogø’s landmass was quadrupled in size.

Here the road and rail tracks diverge, with the rail track diving under a tunnel to the North, while the road continues along the 6790m Eastern bridge.

This Eastern bridge has a single suspended span (without ground support) of 1624m, making it the second longest suspended span in the world. It would actually have been the title holder, at least temporarily, but for a delay in construction which meant that the longer-spanned Akashi-Kaikyo Bridge was completed first.

Prior to the construction of both the Great Belt and Akashi-Kaikyo bridges, the longest span title was held by the Humber Bridge in England, wich reigned from its construction in 1981 until 1998.

Everyone’s favourite Humber fact is that the perfectly vertical towers are actually 36mm² further apart at the top than they are at the bottom, due to the curvature of the earth!

Wikipedia has the complete list of largest suspension bridges and pages on the Great Belt, Sprogø and the Humber Bridge.

Thanks to Jonathan Rawle, Tobias Hader and Cyan