There are iron blocks on the concrete wall of the balcony guardrail.

The iron block on the concrete wall of the balcony guardrail may be to enhance the structural stability and wind resistance of the balcony. In architectural design, balcony guardrails usually use cement walls or reinforced concrete. In order to prevent the balcony guardrail from being damaged or collapsed in natural disasters such as strong winds or earthquakes, metal materials such as iron blocks or steel bars can be added to the cement wall for reinforcement.