This study presents an experimental investigation of fire and smoke propagation through a window opening facing an internal patio (vertical void) in a high-rise building (HRB). Experiments were carried out on a 1:4 scale model composed of two superimposed compartments of identical dimensions (1.23 m × 1.23 m × 2.0 m). Each compartment was equipped with a front window (0.25 m × 0.25 m), while a door measuring 0.50 m × 0.25 m was installed only on the left side of the lower compartment. Two configurations were analyzed: a building with an internal patio (CIAP) and a building without a patio (CISP). Using kerosene as the fire source, a comparative analysis of smoke and hot gas propagation was performed. In the CIAP configuration under windless conditions, the patio acted as a vertical shaft, promoting rapid upward movement of smoke and hot gases to the upper level within 82 seconds. A maximum temperature of 65 °C was recorded in the upper compartment after 400 seconds, accompanied by dense smoke accumulation and reduced visibility. In contrast, the CISP configuration, exposed to ambient airflow, limited the vertical spread of smoke and hot gases, with the upper compartment reaching a maximum temperature of only 39 °C. These results highlight the significant influence of internal patios on chimney effects and emphasize their critical impact on vertical fire propagation in high-rise buildings.