The Temple of Heaven, one of my favorite buildings, is commonly considered the symbol of Beijing. It’s always shown on travel-agency posters when they’re trying to show a montage: The Eiffel Tower, the Temple of Heaven, the Statue of Liberty etc.
For Bangkok, it’s usually Wat Arun, or Temple of the Dawn. Two shots here and here.
More good shots of it here and here.
The Temple of the Emerald Buddha gets the most visitors and is also seen on travel posters, but Wat Arun tends to make it on more. Compact and stately.
Athens: The Acropolis, or more specifically the Parthenon.
Moscow: St. Basil’s Cathedral
Trenton, NJ - The Trenton Bridge over the Delaware. The slogan “Trenton Makes, the World Takes” dates from 1910 and the current bridge from 1928. To most people it means thank God, we’re practically in Pennsylvania, as well as spawning parodies like “Trenton Uses, the World Refuses”.
Rio de Janairo - the big Jesus statue (dude…common)
London - Tower Bridge (not London Bridge), Buckingham Palace, Big Ben/Parliament or the “Ghurkin” building
Kuala Lumpur - Patronas Towers
Amsterdamn - Centrale Station or the Rikesmuseum
Hong Kong - Bank of China Tower
Taipei - Taipei 101
US:
Boston - The Pru, the Handcock building, the Citgo sign behind Fenway’s Green Monster
Los Angeles - Capital Records building
Seatle - Space Needle or Columbia Center
Las Vegas - the MGM Grand or Luxor Casinos
Los Angeles - not a structure, really, but a palm tree next to a freeway. The Hollywood sign. Griffith Observatory.
Long Beach - the Queen Mary.
Some that haven’t been mentioned already (unless I missed them)…
Kuala Lumpur: The Petronas Towers
Kyoto: any of the famous pagodas and temples
Rome: The Colosseum
Saint Petersburg: the Winter Palace
Nashville has the Parthenon, and theirs is in much better shape than the one in Athens.
You’re not fooling me. That’s the headquarters of the Justice League of America. 
Maybe it’s a good thing if you don’t have any iconic structures where you live.
Have you ever seen a disaster movie? The cities with landmarks are always first to get flattened 
I have never seen the CN Tower get flattened in a disaster movie. Toronto’s luck is holding.
On the other hand, Toronto City Hall, the city’s other iconic structure, gets exploded in one of the Resident Evil movies. But it’s playing the headquarters of an evil corporation, so that doesn’t quite count.
Honolulu: Diamond Head
If I were to pick a structure, perhaps Aloha Tower or Iolani Palace, or perhaps the Kamehameha statue. But none have the instant recognition of Diamond Head.
It came close in Canadian Bacon, until Rhea Perlman saved the day.
Lessee, where else is missing?
Rio - Christ the Redeemer statue
Agra - Taj Mahal
Cairo - Pyramids
Atlanta - Airport terminal
LA - the Theme Building at LAX
Miami - Biscayne Bay causeways
Houston - Astrodome
Seattle - Space Needle
Hiroshima - Peace Memorial
St. Louis - Gateway Arch
Well, of course not. Canadians are the ones secretly orchestrating the conspiracy/megalomaniacal plot/alien invasion.
Face-centered cubic.
Nonsense. We’re much too polite for that.
We don’t have any iconic giant monsters either. (That whole moose thing didn’t quite take off.)
