Earth imagery: NASA Blue Marble Next Generation, May 2004, with topography and bathymetry.
Source: NASA WorldWind Java (official NASAWorldWind repository), commit 9ccf6b8ed2ae452ef51e7b1739a7ffd4ef78a403.
https://github.com/NASAWorldWind/WorldWindJava/blob/9ccf6b8ed2ae452ef51e7b1739a7ffd4ef78a403/src/images/BMNG_world.topo.bathy.200405.3.2048x1024.jpg

Copyright 2006-2009, 2017, 2020 United States Government, as represented by the Administrator of the National Aeronautics and Space Administration. All rights reserved.
NASA WorldWind distribution: Apache License, Version 2.0. License text: /textures/LICENSE-APACHE-2.0.txt
Source licensing statement: https://github.com/NASAWorldWind/WorldWindJava/blob/9ccf6b8ed2ae452ef51e7b1739a7ffd4ef78a403/README.md#license

Modifications for My Travel Footprint: resized to 1024x512, encoded as WebP; static 480x480 sphere projection with subtle directional shading derived from that optimized texture. No borders, labels or clouds were added. NASA does not endorse this product.
Original JPEG SHA-256: 7405c39a220bc37519474eba54625a0d1a02b6ad954895147c103a1bc8dd61fb