Visa is a well-established service provider in the banking vertical. London, United Kingdom is the location of their main location.
Right now, Scientific Method, Data Analysis, and Financial Data Analysis are frequently searched for professions at Visa. They recruit for offices in Foster City, CA, Austin, TX, London and 15 other locations within Mexico and other countries. See below for a list of 192 job offers at Visa for jobs like "Senior Problem Manager, ITIL" and "Cybersecurity Platform System Administrator".
Wikipedia provides a helpful article about Visa. Check out their social profile on Google Plus for a different perspective. A resource not to neglect is the company's careers page with more information about job offers and career prospects.