First Art Deco Skyscraper in Europe

Boerentoren, Antwerp

This 97-meter (originally 87,5 m) tower was designed by Jan Van Hoenacker and built from 1929 to 1931. Once it was the tallest office building in Europe.

Read about it (Wiki): EN NL DE

Image: @ by lewishamdreamer Flickr

Spread Your Wings

CANT Z.501 Gabbiano flying boat
Italy, 1934

Palace of Soviets, Moscow

Design: Boris Iofan, Vladimir Shchuko and Vladimir Gelfreikh
If built, it would have become the world's tallest structure (420 m). Construction started in 1937, and was terminated by the German invasion in 1941. In 1941-1942, its steel frame was disassembled for use in fortifications and bridges. Construction has never been resumed.

Read about it (Wiki, EN)
Sketch © МУАР

Battersea Power Station

Designed by Sir Giles Gilbert Scott, once it was the largest brick building in Europe.

Read about it (Wiki, EN)

Four-Wheeled Rocket

Wikow aerodynamic concept car
Czechoslovakia, 1931

Stout. Scotch. Streamline

Belgian beer truck
1930s

Zenith Special Aviators' Watch

IWC of Schaffhausen calls itself a creator of the world's first specialized aviator's wristwatch - glorious Mark IX (1936). This claim is arguable to some extent - after all, Longines' Lindbergh Watch was introduced two years earlier, and dozens of other watchmakers supplied military and civil aviators with anti-magnetic chronometers from the early 1920s.
This Swiss Zenith Special (c. 1930) served with the German Luftwaffe. Right before the WWII Zenith chronometers were the French Air Force standard issue.