megatall

A megatall building is a structure exceeding 600 meters in height, placing it above the supertall classification that tops out around 500 meters. The upper limit sits informally near 900 meters, though this boundary remains fluid as engineering pushes higher. These are among the world's rarest structures: fewer than a dozen exist or are under construction, concentrated in Gulf states and China where regulatory, zoning, and economic conditions permit such ambition.

The Burj Khalifa in Dubai remains the benchmark at 828 meters; Makkah Royal Clock Tower in Saudi Arabia reaches 601 meters. Projects like the proposed Jeddah Tower in Saudi Arabia target 1,000 meters, which would exceed even the megatall category. These buildings serve mixed functions: hospitality, residential, office, and often include observation decks that justify the extreme height economically.

Engineering demands at this scale

Structural systems must manage wind loads that increase dramatically with height, using moment-resisting frames, bundled tube designs, or diagrid geometries. Concrete grades often reach 80 MPa or higher in lower sections. Tuned mass dampers or active dampers control sway. Elevator systems become transport networks: express lifts serve mid-level transfer floors, reducing travel distance in upper zones. Pressurization, mechanical systems, and egress planning follow specialized codes that many jurisdictions lack until such projects arrive.

Material logistics and construction methodology dominate project timelines. Delivering concrete, rebar, and curtain wall components to heights exceeding 800 meters demands specialized tower cranes, climbing formwork systems, and external hoisting rigs. Weather windows narrow; wind restrictions halt work frequently. Construction duration typically spans 5 to 7 years, with costs reaching USD 1 billion to USD 2 billion before finishes.

The term "megatall" emerged in architectural journalism during the 2010s as supertall buildings became routine in major cities and developers pursued ever-greater heights as branding. Unlike supertall, which has loose industry acceptance, megatall remains informal: no single body defines it rigidly. Structural engineers and developers use it to signal a qualitative shift in design complexity, regulatory novelty, and construction risk rather than a formally codified threshold.