The cathedral was built directly on top of the destroyed Aztec Templo Mayor using stones from the pyramid itself — a deliberate act of architectural conquest. Because the entire city was built on a drained lakebed, the cathedral has been sinking unevenly for 400 years. One corner has sunk 2.5 metres more than the others, and engineers have spent decades trying to stabilise it with everything from concrete injections to micro-piles driven 40 metres into the mud.

The Templo Mayor was rediscovered by accident in 1978 when electrical workers digging at night hit a massive Aztec monolith — the Coyolxauhqui Stone. This chance discovery triggered one of the most dramatic archaeological excavations of the 20th century: an entire pyramid complex was unearthed from beneath a colonial city block. The Aztec builders had constructed seven successive temples on the same spot, each one built directly over the previous, making the site a 3D timeline of Aztec architectural evolution.

The Palacio de Bellas Artes sinks more than any other monument in Mexico City — over 4 metres since construction began. Because the marble-floored building sinks unevenly into the lakebed, floors have had to be cut and realigned multiple times, and the main entrance stair now requires different numbers of steps each decade. It contains the world-famous Tiffany stained-glass curtain showing the Popocatépetl and Iztaccíhuatl volcanoes — weighing 24 tons and made of nearly a million pieces of opalescent glass.

Chapultepec Castle is the only royal castle in the Americas that housed actual reigning monarchs. After Emperor Maximilian was executed by firing squad in 1867, Empress Carlota descended into madness, believing she was being poisoned. She spent the remaining 60 years of her life in seclusion in a Belgian castle, still maintaining she was the Empress of Mexico. The hill itself was sacred to the Aztecs centuries before the castle existed.

The Pyramid of the Sun is built directly over a 100-metre-long man-made tunnel leading to a natural cave, which the Teotihuacanos considered the womb of the gods. The pyramid base (225 metres per side) almost exactly matches the dimensions of the Great Pyramid of Giza — built 2,500 years earlier on the other side of the world, by a civilisation that had no contact with Egypt. The coincidence suggests that a pyramid with a square base of 225 metres may be a universal solution to building a stable monumental structure at that scale.

After a catastrophic bus accident at age 18, Frida Kahlo spent much of her life painting from a four-poster bed in this house — yet she became one of the most recognisable artists of the 20th century. The intense blue walls were painted by her photographer father to evoke Mexican folk culture. Her ashes are displayed in the house inside a frog-shaped urn, and the house contains her original paintbrushes, corsets, and prosthetic leg — preserved exactly as she left them.

Inside the National Palace, Diego Rivera's mural "The Epic of the Mexican People" covers 450 square metres of wall space — one of the largest murals in the world. Painted between 1929 and 1935, it presents a single continuous narrative moving from the Aztec civilisation through the Spanish conquest to the Mexican Revolution, all visible from one spot. Rivera included hidden details among the hundreds of figures: depictions of historical figures whose identities were only confirmed decades after his death.