The Rain Vortex, sponsored as the HSBC Rain Vortex, is the world's largest and tallest indoor waterfall, standing at 40 metres (130 ft) high. Recirculating rain water is pumped to the roof to free fall through a round hole at up to 37,850 liters (8,330 imp gal; 10,000 U.S. gal) per minute to a basement-level pool.

The HSBC Rain Vortex at Jewel Changi Airport is the world's tallest indoor waterfall, standing at 40 meters. It operates as a sophisticated closed-loop system designed for both aesthetic beauty and environmental sustainability. Rainwater is collected from the building’s massive toroidal (donut-shaped) roof and channeled toward the center. As the water pours through the oculus, it creates a natural cooling effect for the forest valley below. To maintain the flow during dry spells, the system recirculates a massive volume of water using powerful pumps hidden in the basement levels. At night, the waterfall serves as a canvas for a high-tech light and sound show, where 360-degree projections are mapped onto the falling water. The "vortex" effect is controlled by the shape of the glass funnel, which ensures the water falls in a neat, controlled column rather than a chaotic splash, eventually disappearing into a large acrylic basin that filters the water before it is pumped back to the top for the next cycle.

The Rain Vortex is a stunning architectural and engineering feature located at Jewel Changi Airport in Singapore. It is the world’s tallest indoor waterfall, standing at 40 meters (131 feet) high. Here’s how it works:

1. Water Collection and Recycling

• Rainwater is collected from the glass-and-steel dome of Jewel Changi Airport.
• The water is then filtered and treated before being recirculated to create the Rain Vortex.

2. Pumping System

• A powerful pumping system pushes the water to the top of the vortex structure.
• The water is released from a circular opening at the top, creating a seamless waterfall effect.

3. Gravity and Design

• The water cascades down through the center of the building, guided by gravity and the aerodynamic design of the vortex structure.
• The shape of the vortex ensures the water flows smoothly and creates a visually mesmerizing effect.

4. Lighting and Effects

• The Rain Vortex is enhanced by LED lighting, which creates stunning visual displays, especially at night.
• The lights can change colors and patterns, adding to the spectacle.

5. Cooling and Humidity Control

• The Rain Vortex also serves a functional purpose by helping to cool the indoor environment and maintain humidity levels within Jewel Changi Airport.

6. Sustainability

• The system is designed to be energy-efficient, using recycled water and minimizing waste.
• It aligns with Singapore’s focus on sustainability and innovative urban design.

The Rain Vortex is not only a breathtaking visual centerpiece but also a testament to the integration of art, engineering, and environmental consciousness. It has become an iconic symbol of Singapore’s Changi Airport and a must-see attraction for visitors.