Fast fact: When the Transamerica Pyramid's three years of construction began in 1969, signs around the site proclaimed it "a San Francisco landmark since 1972."
"The Transamerica Pyramid put San Francisco's downtown on the map." -- Michael Greene.
A stark contrast to San Franciso's picturesque wooden Victorian houses, this quartz-covered skyscraper juts into the sky like a rocket.
Though not comparable to today's futuristic skyscrapers, the 260-meter pyramid was the city's most recognizable building for decades.
Designed by architect William Pereira, the structure has an unconventional tapered design -- imitating a tree trunk -- that allows natural light and fresh air to trickle down to adjacent streets.
Without obstructing much of the tranquil neighborhood, this slender style, together with an earthquake-safe design, allowed the building to get around strict building laws in the city, reaching a height once unheard of in San Francisco.
The Transamerica Pyramid isn't open to the public, though there's a decent website with images and facts on the building.
Transamerica Pyramid, 505 Sansome St., San Francisco
Bank of China Tower, Hong Kong
Height: 367.4 meters
Cost to build: N/A
Completion date: May 1990
Fast fact: The building was criticized by feng shui masters for its sharp corners, which reportedly bring bad luck to its neighbors (notably the HSBC main building).
The Bank of China Tower was the first skyscraper outside of the United States to surpass the 305-meter mark and was once the tallest building in Hong Kong.
The unusual crystalline-like structure is inspired by the bamboo plant, mimicking its strength, vitality and growth.
Chinese-American architect I.M. Pei had to modify the design before construction began.
It has for years been one of the most distinctive buildings in Hong Kong, out-shining taller neighbors.
Together with Two IFC, the tower is part of the city's Symphony of Light show, which illuminates Hong Kong's harbor every night at 8 p.m.
The observation deck on the 43rd floor offers stunning views of Central, one of Hong Kong's busiest districts.
Bank of China Tower, 1 Garden Road, Central, Hong Kong Island
Kingdom Centre, Riyadh, Saudi Arabia
Height: 302 meters
Cost to build: $1 billion
Completion date: 2002
Fast fact: Riyadh's building code forbids any building to have more than 30 usable floors, but doesn't impose height restrictions. The big void near the top of the Kingdom Centre means the building uses only 30 floors.