Instituto Geográfico Nacional (Spain)
![Headquarters (Madrid)](https://upload.wikimedia.org/wikipedia/commons/5/59/Instituto_Geogr%C3%A1fico_Nacional_%28Madrid%29_02.jpg)
Since 2015, most of its products (including ''MTN50'' and ''MTN25'' topographic maps, and ''PNOA'' aerial photographies) are freely available online, and licensed under a CC-BY-4.0-like license, as ''FOM/2807/2015'' decree requires its products must be released under a free license. Provided by Wikipedia