Inside the largest city by population in all of the Americas is a surprisingly pristine 2.27 mile or 3.65-kilometer-wide circular impact crater. This feature is known as Colonia Crater, and can be found inside the metropolitan area of Sao Paulo within Brazil. Today's video will discuss how this feature formed, a mystery surrounding it, and why more studies are needed. Thumbnail Photo Credit: Google Earth, Image Landsat / Copernicus, Image © 2025 Maxar Technologies. This image was overlaid with text, and then overlaid with GeologyHub made graphics (the image border & the GeologyHub logo). Estimates on asteroid diameter, velocity, tnt energy equivalent, initial crater depth, and effects from the impact (including earthquake magnitude generated and wind speeds generated) in this video were sourced using the calculator at https://impact.ese.ic.ac.uk/ImpactEarth/ImpactEffects/, which was used with permission. If you would like to support this channel, consider using one of the following links: (Patreon: http://patreon.com/geologyhub) (YouTube membership: https://www.youtube.com/channel/UCYeGh5VML5XPr5jYnzh3J6g/join) (Gemstone & Mineral Etsy store: http://prospectingarizona.etsy.com) (GeologyHub Merch Etsy store: http://geologyhub.etsy.com) Google Earth imagery used in this video: ©Google & Data Providers This video is protected under "fair use". If you see an image and/or video which is your own in this video, and/or think my discussion of a scientific paper (and/or discussion/mentioning of the data/information within a scientific paper) does not fall under the fair use doctrine, and wish for it to be censored or removed, contact me by email at [email protected] and I will make the necessary changes. Various licenses used in sections of this video (not the entire video, this video as a whole does not completely fall under one of these licenses) and/or in this video's thumbnail image (and this list does not include every license used in this video and/or thumbnail image): CC BY 2.0: https://creativecommons.org/licenses/by/2.0/legalcode CC BY 4.0: https://creativecommons.org/licenses/by/4.0/legalcode Sources/Citations: [1] Velázquez Fernandez, Victor & Riccomini, Claudio & Sobrinho, José & Pletsch, Mikhaela & Sallun, Alethéa & Sallun Filho, William & Hachiro, Jorge. (2013). Evidence of Shock Metamorphism Effects in Allochthonous Breccia Deposits from the Colônia Crater, São Paulo, Brazil. International Journal of Geosciences. 4. 274-282. 10.4236/ijg.2013.41A025., CC BY 4.0. [2] Victor F. Velázquez, Rodrigo F. Lucena, Jose M. Azevedo Sobrinho, Alethéa E. Martins Sallun, William Sallun Filho. (2017). Petrographic Investigation of Target Rock Transformation under High Shock Pressures from the Colônia Impact Crater, Brazil. Earth Science Research. Canadian Center of Science and Education. 10.5539/esr.v7n1p13., CC BY 4.0. [3] Velázquez, V.F., Colonna, J., Sallun, A.E.M. et al. The Colônia Impact Crater: Geological Heritage and Natural Patrimony in the Southern Metropolitan Region of São Paulo, Brazil. Geoheritage 6, 283–290 (2014). https://doi.org/10.1007/s12371-014-0121-0 [4] RICCOMINI, C., CRÓSTA, A.P., PRADO, R.L., LEDRU, M.-P., TURCQ, B.J., SANT’ANNA, L.G., FERRARI, J.A. and REIMOLD, W.U. (2011), The Colônia structure, São Paulo, Brazil. Meteoritics & Planetary Science, 46: 1630-1639. https://doi.org/10.1111/j.1945-5100.2011.01252.x [5] G. Collins & others, "A numerical assessment of simple airblast models of impact...", Meteoritics & Planetary Science, https://doi.org/10.1111/maps.12873 (2017), CC BY 4.0 0:00 Sao Paulo Impact Crater 0:26 Colonia Crater 1:38 Unusually Shallow Crater 2:51 Comet or Asteroid? 3:57 Impact Hazards