At 40m, Jewel Changi Airport's waterfall, the world's tallest indoor one, makes such a splash that people standing nearby often get a little wet.
The water never stops, so there are always puddles on the floor to mop up, for the safety of visitors.
Cleaners previously had to spend 10 minutes each time doing this manually at one-to two-hour intervals. But since January, the onerous task has been taken over by two tireless workers.
They are Jewel's LeoScrub robots, built by local company LionsBot International and part of a growing fleet of automatons helping to keep Changi Airport humming along daily.
Cleaning robots like the LeoScrubs make up the bulk of the 47 robots in Jewel and the airport's terminals. But these robots are also increasingly being called upon to interact with visitors in a variety of ways.
The LeoScrubs, for example, sport a QR code on their frames that visitors can scan with their phones to open a menu with questions they can ask the robots.
These include, if visitors are so inclined, asking the robots to sing.
Jewel is also trialling a concierge robot that provides directions to shops within the mall and doubles as a ticketing kiosk for tourist attractions, among other services.
The concierge robots will be deployed later this year.
"The use of robots has helped to ease the more laborious tasks of our staff, as well as those of our partners, at Jewel," said Jewel Changi Airport head of user experience Kelvin Tan. He added that staff have, as a result, been able to work smarter and be more productive.
For example, cleaners typically make the rounds once a day to collect trash from each of Jewel's shops. This could take about 1½ hours for just one level of the mall.
Four LeoPull robots, lookalike "sisters" of the LeoScrubs, now handle trash collection on Jewel's third level, with more to be deployed on other levels by the end of the year.
Each LeoPull tows a large customised trash bin and will stop in front of each shop and ring a bell to notify the tenant of its arrival. It does this entirely on its own, having been programmed with the route.
A suite of sensors also helps the robot avoid obstacles and people, and lets its operators know what it is up to at any one point. The operators can also give it instructions, if needed, via an app.
Though they may be head-turners, the LeoScrubs and LeoPulls are not Changi Airport's most popular robots.
That distinction belongs to the 1.3m-tall Delight robot, which roves around the confines of Jewel's Canopy Park twice a day, offering visitors free bottled drinks and sweets.
"The Delight robot has proven very popular since Canopy Park opened last year," said Jewel Changi Airport's user experience executive Euguene Tan, who is part of the team that oversees Jewel's robots.
"It is programmed to follow a set route. But we can also manually trigger it to return when the drinks run out."
When The Straits Times visited Canopy Park last Wednesday, the Delight robot had barely gone 5m from its starting point when it was mobbed by visitors of all ages.
