25 of mankind's greatest engineering achievements By Tamara Hinson, for CNN

25 of mankind's greatest engineering achievements

By Tamara Hinson, for CNN

July 5, 2013 -- Updated 0635 GMT (1435 HKT)

The Palm islands comprise approximately 100 million cubic meters of rock and sand. 
In total, 210 million cubic meters of rock, sand and limestone were reclaimed (through dredging) to create the islands, with 10 million cubic meters of rock used in the outer ring alone. The rocks used for both islands were transported from 16 quarries throughout the UAE and the materials used are enough to build a wall that could circle the world three times. Completion date:September 24, 2008.

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The Palm, Dubai

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STORY HIGHLIGHTS

• Dubai's Palm Islands comprise 100 million cubic meters of rock and sand
• Pyramid of the Sun in Teotihuacan, Mexico, is third-tallest pyramid in the world
• London Underground is used for more than 1 billion journeys every year

(CNN) -- The last few months have seen a fair number of impressive construction plans announced, from Norway's intention to create the world's first shipping tunnel, to Maldives' plans for aspace-age underwater hotel, to Dubai's plans for the world's biggest shopping mall.

How do these announcements stack up against what's already out there?

We've compiled 25 of what we think are some of the most impressive engineering/construction achievements to date, taking into consideration the era in which they were built and the knowledge and materials that were available to the designers.

Many of these were inspired by the human impulse to travel, and those that weren't can now be enjoyed by travelers today.

Engineering can of course also include electronics and other micro feats -- arguably computers and smartphones are among the most successful, popular and influential pieces of engineering ever created -- but we're interested here in big, bold and brave.

Click through the gallery to see our selection, then let us know if you have any further additions in the comments.

Getting there

The Palm, Dubai, UAE

There are several tour operators within Dubai offering boat tours of the Palm.

Aqueduct of Segovia, Segovia, Spain

Segovia is an easy day trip from Madrid and can be reached by both train and bus.

Great Wall of China, China

Beijing International airport is the closest airport to any point of the Great Wall of China -- it's just a short taxi ride to the section known as Badaling Great Wall and there are also regular bus services.

Taj Mahal, Agra, India

There are regular bus and train services connecting New Delhi with Agra.

Trans-Siberian railway, Russia

The full journey starts in Moscow and ends in Vladivostok, but passengers can join at numerous towns and cities en route.

Burj Khalifa, Dubai, UAE

The Burj Khalifa is located in downtown Dubai and is well-connected by public transport.

Akashi Kaikyō Bridge, Akashi Strait, Japan

The bridge is a short drive from Kobe Airport.

White Pass and Yukon Route Railroad, Canada

Excursions start from Fraser, British Columbia. The nearest airport is in Vancouver.

Tokyo Sky Tree, Tokyo

From Ueno Station (Tokyo Metro Ginza Line), transfer to the TOBU SKYTREE Line at Asakusa Station - the Skytree stop is a 14-minute journey.

International Space Station

Astronaut qualifications and a rocket.

Teotihuacan, Mexico

There are regular buses to Teotihuacan from Mexico City.

Panama Canal, Panama

The Panama Canal is best explored by organized boat tour, but Panama City's Tocumen International Airport is the nearest airport.

Taipei 101, Taipei, Taiwan

Take the Taipei MRT-Bannan Line to MRT Taipei City Hall Station. From there, walk towards Xinyi Road from exit number two to Taipei 101.

Grand Canyon Skywalk, Arizona, United States

The nearest airports are Phoenix Sky Harbor Airport (PHX), or the Las Vegas Airport(LVS). It takes around two hours to drive to the Skywalk from Las Vegas, but organised tours which depart from the city are also available.

Shanghai World Financial Center, Shanghai

The building is a 20-minute walk from Dongchang Road Pier. The nearest subway station is Lujiazui Station.

Millau Viaduct, Millau, France

The nearest train station can be found in the town of Millau, which is well connected to cities and towns throughout France. The closest airport is Rodez-Marcillac -- a 25-minute drive away.

London Underground, London

London's Heathrow Airport is connected to the London underground.

Kansai Airport, Osaka, Japan

Kansai International Airport is connected to most of the major international hubs. Osaka is two hours from Tokyo on the Shinkansen bullet trains.

Hoover Dam, Arizona/Nevada, United States

The nearest airport is in Las Vegas, 32 miles away.

Great Pyramid of Giza, Egypt

There are regular bus services from the centre of Cairo and it's also just a short taxi ride.

Golden Gate Bridge, San Francisco

There are regular buses to the bridge from downtown San Francisco, Marin County and Sonoma County.

Eiffel Tower, Paris

The closest Paris Metro station to the Eiffel Tower is Champ de Mars.

Confederation Bridge, Prince Edward Island, Canada

Travel to Prince Edward Island by ferry from New Brunswick. Charlottetown Airport is the island's largest airport.

Colosseum, Rome

There are regular buses to the site, and it's also possible to get there by tram -- look for the "Colosseo" stop.

CN Tower, Toronto, Canada

The CN Tower is in the heart of downtown Toronto. There are regular buses to Bremner Boulevard, where the tower is located.