Angel of Independence's staircase expansion

The Angel of Independence, a prominent monument in Mexico City, originally had nine steps at its base when it was inaugurated in 1910. Over time, the staircase has grown to 23 steps, with 14 added due to ground subsidence, a long-standing problem in the city.

Mexico City's subsidence origins

Mexico City is built on the dried-up bed of Lake Texcoco, which was drained by Spanish conquistadors in the 17th century. The lake bed has been compacting over time due to the weight of urban development and the pumping of groundwater, which supplies about 60 percent of the city's drinking water.

Subsidence rates and measurements

Studies by Cigna and Tapete show that the ground in the city center sinks between 1 and 9 centimeters per year. Other research indicates that in some areas, the subsidence rate was as high as 5 centimeters per year as early as 1895.

Recent satellite observations

The NISAR satellite, launched in July 2025 by NASA and the Indian Space Agency, observed that the ground at the main airport and the base of the Angel sinks about 24 centimeters per year. This data highlights the ongoing challenge of subsidence in the region.

Historical expansion of the steps

The addition of 14 steps over 116 years represents an average of one step every 8 years. However, the exact dates of these additions are not specified in available sources.

Monument's design and materials

The steel structure of the Angel of Independence is covered with quarried stone and features garlands, palms, and rings bearing the names of figures from Mexico's Independence. The monument is designed in the style of a Corinthian column of Victory.

Subsidence's impact on infrastructure

Subsidence has caused damage to infrastructure in Mexico City, including the subway, roads, buildings, and pipelines. Studies show that the subsidence is differential, especially in areas where stable volcanic rock meets highly compressible sediments.

Monument's historical significance

The Angel of Independence remains a key landmark in the capital, with a staircase of 200 steps leading to a viewing platform above the city. The monument was damaged in earthquakes in 1957 and 1985 but has remained a symbol of Mexico's independence.