The Burj Khalifa is so tall you can watch the same sunset twice by taking the elevator up

Standing at ground level in Dubai as the sun dips below the horizon, a visitor could watch daylight fade into evening, then step into an elevator, ride up more than half a mile of steel and glass, and catch the last sliver of that same sunset all over again from an observation deck near the top. It sounds like a novelty trick, but it is simple geometry: height buys extra minutes of daylight, and no building on the planet has more height to spend than this one.

An Engineering Response to Extreme Height

Rising more than 2,700 feet above the desert, the tower held the record for the world’s tallest building by a wide margin when it opened, and it has kept that title ever since despite more than a decade of ambitious skyscraper projects elsewhere trying to challenge it. Reaching that height required engineers to solve problems that simply do not exist at more conventional skyscraper scales, from wind loads that increase dramatically with altitude to the sheer logistics of pumping concrete higher than any construction crew had ever pumped it before.

The Burj Khalifa solved much of that challenge with a distinctive tapering, Y-shaped floor plan, a design that reduces wind pressure on the structure as it narrows toward the top while also giving every residential and hotel floor more exterior wall for windows. The design came from American architect Adrian Smith, working with an architecture firm with a long history of skyscraper engineering, and it drew inspiration in part from a regional desert flower whose petaled structure mirrors the tower’s stepped, spiraling profile.

How Extra Altitude Delays a Sunset

The sunset trick is a straightforward consequence of the Earth’s curvature. Because the horizon drops away as an observer’s elevation increases, someone standing at the top of a very tall building can still see the sun above that horizon for a short while after it has already disappeared from the view of someone standing at street level directly below. The taller the vantage point, the longer that delay lasts, and at a height measured in hundreds of stories rather than tens, the effect becomes large enough to notice without instruments, stretching what would be an unremarkable few seconds atop an ordinary building into several extra minutes of visible daylight.

Observation decks built into the tower’s upper floors have made that phenomenon into something close to a tourist attraction in its own right, drawing visitors specifically at sunset hours to experience the delay firsthand. Photographers and physics enthusiasts have documented the effect from the building for years, timing exactly how much longer the sun remains visible from the highest publicly accessible floor compared with the plaza at the tower’s base.

A Symbol Built Into a Growing City

The tower opened in 2010 as the centerpiece of a much larger downtown development built around it, complete with a shopping mall, an artificial lake with choreographed fountains, and a dense cluster of residential and hotel towers that grew up around the original structure in the years that followed. Its completion marked a turning point for Dubai‘s skyline and its global profile as a tourism and business destination, transforming what had been a relatively low-rise stretch of desert into one of the most photographed urban views in the world.

More than a decade after it opened, the building still draws millions of visitors annually specifically to ride its high-speed elevators to the observation floors, many of them timing their visit deliberately around sunset to see the light-bending effect that height alone makes possible, a reminder that record-setting architecture can create genuinely new experiences rather than simply taller versions of familiar ones.

The Structural System That Made the Height Possible

Engineers relied on a structural approach known as a buttressed core, in which a central hexagonal concrete spine is braced by three wings extending outward, each supporting the others against wind and gravity loads the way a tripod stabilizes a camera. That arrangement let the tower taper as it rises, with each of the three wings stepping back at different heights so no single face of the building ever grows too wide relative to its supporting core, reducing the wind forces that would otherwise threaten a conventional rectangular tower at that height.

Construction relied on pumping concrete to heights that had never been attempted before, requiring specially engineered pumps and a concrete mixture formulated to remain workable during the long vertical journey from ground-level mixers to the upper floors. Builders also had to account for how much the tower would sway in high winds and how much its concrete core would shorten over time as the enormous weight above compressed the material below, adjustments that had to be calculated years in advance and built into the construction schedule itself. That combination of structural engineering and long-range planning is a large part of why the record has stood for as long as it has, since matching or exceeding that height requires solving the same set of problems all over again from scratch.

This article was produced with the assistance of AI and reviewed by Morning Overview editors.

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