This is part 9 of A Trivial Pursuit, a 25-part puzzle hunt. Each part is solvable on its own, with the exception of the meta-puzzle at the end.
Colourblind-friendly version available here.
Puzzle in text format, for accessibility:
Total height of the Empire State Building (including antenna), in feet [Gn] [Gy] [Gy] [Gy]
Year that the cathedral in Lincoln, UK, became the world's tallest building [Gn] [Gy] [Gy] [Gy]
Number of steps in the Eiffel Tower [Gn] [Gy] [Gy] [Gy]
Year that Europe's current tallest free-standing structure was completed [Gn] [Gy] [Gy] [Gy]
Year of the inauguration of the Burj Khalifa [Gy] [Gy] [Y ] [Gy]
*YEAR* [4] [Gn] [Gn] [Gn] [Gn]
Frank ----- Wright (US, 1867) [Gy] [Gy] [Gy] [Gy] [Gy]
----- Niemeyer (Brazil, 1907) [Gy] [Gy] [Gy] [Gn] [Gy]
----- Piano (Italy, 1937) [Gy] [Gy] [Y ] [Gy] [Gy]
Zaha ----- (Iraq, 1950) [Gy] [Gn] [Gy] [Gy] [Gy]
César ----- (Argentina, 1926) [Y ] [Gy] [Gy] [Gy] [Gy]
*COUNTRY* [5] [Gn] [Gn] [Gn] [Gn] [Gn]
Sixth and Guadalupe [Y ] [Gy] [Gy] [Gy] [Gy] [Y ]
Vasco da Gama Tower [Y ] [Gy] [Gy] [Gy] [Y ] [Y ]
BCEAO Tower [Gy] [Y ] [Gy] [Gy] [Y ] [Gn]
DC Tower 1 [Gy] [Gy] [Gy] [Gy] [Gn] [Y ]
The Shard [Y ] [Y ] [Y ] [Gn] [Gy] [Gy]
*CITY* [6] [Gn] [Gn] [Gn] [Gn] [Gn] [Gn]
First name of architect who was born in [6] in [4] and worked in [5] [Y ] [Y ] [Gy] [Gy] [Gy] [Y ] [Gn]
Kingdom where he was born… [Gy] [Gy] [Gy] [Y ] [Y ] [Y ] [Y ]
…in this modern-day country [Gy] [Gy] [Y ] [Gy] [Gy] [Y ] [Y ]
His naturalised surname on becoming a US citizen [Gn] [Y ] [Gy] [Gn] [Gy] [Gn] [Gy]
US architect under whom he worked at the start of his career [Gy] [Y ] [Gy] [Gy] [Y ] [Y ] [Gy]
*The relevant final answer to this puzzle* [Gn] [Gn] [Gn] [Gn] [Gn] [Gn] [Gn]