![](\"http:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2018\/11\/mexico_city\/18926768-1-eng-GB\/Mexico_City_small.jpg\")
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\nThe Copernicus Sentinel-1 mission takes us over Mexico City. This huge, densely-populated capital can be seen in the top right of the image. It is home to almost nine million people, with the Greater Mexico City area recording a population of over 21 million. This makes it the largest Spanish-speaking city in the world.\n<\/p>\n
\nThis striking image has been created using three Copernicus Sentinel-1 acquisitions from 28 July, 27 August and 26 September 2018, overlaid in red, green and blue, respectively. Where we see explosions of colour, changes have occurred between the different acquisitions.\n<\/p>\n
\nIn the left of the image, three bodies of water are shown in black: Villa Victoria, Valle de Bravo, and Tepetitl\u00e1n. Water is significant to the development of Mexico City, which is thought to have been built over a lake by the Aztecs around 1325.\n<\/p>\n
\nToday, the city finds itself in a precarious situation in terms of water supply in spite of the regular flash floods and heavy rainfall it experiences during the wet season from June and September.\n<\/p>\n
\nIn the top right, we can see the round structure of El Caracol meaning \u2018the snail\u2019 in Spanish. Currently used as a reservoir for industrial facilities within Mexico City, there are plans for this to become a wastewater treatment plant. A 62 km-long sewer tunnel is also due to begin operating this year. \n<\/p>\n
\nThe Cumbres del Ajusco national park is shown to the southwest of the capital, in an area of the image that shows colourful dots forming a circle. Famous for being up to almost 4000 m above sea level at its highest elevation, it is one of many national parks surrounding the capital.\n<\/p>\n
\nVolcanoes are also dotted around this area. Popocat\u00e9petl, to the south east of Mexico City, last erupted in September 2018.\n<\/p>\n
\nSentinel-1 is a two-satellite mission to supply the coverage and data delivery needed for Europe\u2019s Copernicus environmental monitoring programme. The satellites each carry an advanced radar instrument to provide an all-weather, day-and-night supply of imagery of Earth\u2019s surface.\n<\/p>\n