One World Trade Center, New York
Height: 541 meters
Cost to build: $3.9 billion
Completion date: May 2013
Fast fact: The height of 1,776 feet is a symbolic reference to the year in which the United States' Declaration of Independence was signed.
Part memorial, part statement, part billion-dollar office complex, One World Trade Center is one of the more controversial buildings of the new century.
Designed by David Childs (Skidmore Owings & Merrill), the skyscraper sits on the spot of the former 6 World Trade Center building, destroyed in the September 11, 2001, terrorist attacks.
It's meant to be functional, as well as beautiful.
"We fully understand the iconic importance of the tower, but it also has to be a highly efficient building," Childs has said. "If this building doesn't function well, if people don't want to work and visit there, then we will have failed as architects."
Security features such as biological and chemical filters in the ventilation system, reinforced walls and pressurized stairwells, as well as a stairwell exclusively for firefighters, have been included in the event of a future emergency.
One World Trade Center, West Street/Vesey Street, New York
Marina Bay Sands, Singapore
Height: 194 meters
Cost to build: $6.3 billion
Opening date: April 2010
Fast fact: Marina Bay Sands is one of the world's most expensive standalone casino properties, with total costs estimated at more than $6 billion.
It's a little lopsided, with one end of the surfboard-like "SkyPark" overhanging one of the three towers by nearly 70 meters, but what Marina Bay Sands lacks in symmetry it makes up for in big numbers.
The hotel has 2,561 rooms.
There's a 150-meter infinity swimming pool within the 340-meter SkyPark.
More than $6 billion went into the property's development, including nearly $1 billion for the land.
But Las Vegas Sands chairman Sheldon Adelson expects to draw even by 2015 at the latest, with the casino alone generating annual profits of $1 billion.
Architect Moshe Safdie says the hotel's design was inspired by a deck of cards. Feng Shui consultants were also involved in the design approval process, though the feng shui aspects of the build are controversial.
Some claim the swimming pool on top of the towers appears to drown the financial district of the city, while others say the water will bring opportunities.
Marina Bay Sands, 10 Bayfront Ave., Singapore; +65 6688 8868