Snowcapped mountain peaks. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3287992/free-photo-image-aerial-view-birdflyview-cc0Free Image from public domain licenseStar Alliance & Air Asia airlines, Singapore Changi airport, 8/06/2016. https://www.rawpixel.com/image/6113002/photo-image-public-domain-technology-skyFree Image from public domain licenseView from a mountain slope on a craggy ridge shrouded in mist. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3288329/free-photo-image-adventure-austria-blue-skyFree Image from public domain licenseRural towns form maze like patterns in a country landscape. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3287022/free-photo-image-balloon-air-hot-aerial-viewFree Image from public domain licenseYangtze River Express jumbo jet flight, location unknown, 11/08/2015. https://www.rawpixel.com/image/6112352/photo-image-public-domain-technology-skyFree Image from public domain license