jacked a thin spire
Hi
Would you explain what 'jacked a thin spire ' mean?

In 1929, auto tycoon Walter Chrysler took part in an intense race with the Bank of Manhattan Trust Company to build the world’s tallest skyscraper. Just when it looked like the bank had captured the coveted title, workers at the Chrysler Building jacked a thin spire hidden inside the building through the top of the roof to win the contest (subsequently losing the title four months later to the Empire State Building). Chrysler also decorated his building to mirror his cars, with hubcaps, mudguards, and hood ornaments.

Question

jacked a thin spire
Hi
Would you explain what 'jacked a thin spire ' mean?

In 1929, auto tycoon Walter Chrysler took part in an intense race with the Bank of Manhattan Trust Company to build the world’s tallest skyscraper. Just when it looked like the bank had captured the coveted title, workers at the Chrysler Building jacked a thin spire hidden inside the building through the top of the roof to win the contest (subsequently losing the title four months later to the Empire State Building). Chrysler also decorated his building to mirror his cars, with hubcaps, mudguards, and hood ornaments.

Answer

A jack is a device for hoisting or lift heavy objects. You can use the word as a verb - "I jacked/raised up my car so I could replace the tyre".

A spire is a conical or pyramidal structure that sits on top of a building and terminates to a smallish point. Imagine a flagpole that is very wide at the bottom, but ends very narrow or at a point - that is something like a spire.

In your example, a secret spire was built just below the roof of the building. Then it was raised/hoisted/jacked through the roof so that the bottom of this spire sat on the roof with the peak/top of the spire going many metres higher.