Proving the strength of the monocoque/unibody

The Traction used a welded unitary body / chassis. Most cars of the era used a chassis onto which the coachwork or body was fitted.

The American firm Budd had developed a new 'Unibody' technique comprising a monocoque or single steel structure that replaced the chassis and incorporated a shell onto which panels such as wings, bonnet and doors were fitted. This resulted in a reduction in weight of some 70 kg. Unlike the traditional chassis and separate body, this technique lent itself to mass-production and automation of the production line

Needless to say, many viewed it with great suspicion; believing that a chassis was far stronger.
So on 25th May 1934 Citroën arranged a demonstration of the car's inherent strength by repeating the exercise they had conducted with the introduction of the Tout Acier (all steel) body B10 - a Traction 7CV, together with a conventionally built car were driven 8 m off a cliff. The exercise was filmed for posterity.

After rolling over twice, the car landed on its wheels. The bonnet was destroyed but all four doors could be opened, apart from the rear screen, all the glass was intact and the car could still be driven.
Contrast this with the other, conventionally constructed car.
Needless to say, all modern designs are of monocoque construction.