Microsoft is providing a free virtual machine that comes preloaded with Windows 10 Enterprise, Visual Studio 2017, and various utilities in order to promote the development of Universal Windows Platform apps. Each of these images are about 17-20GB when extracted from the downloaded archive and include almost everything you need to develop Windows 10 apps. Included on the site where you download the VMs are a wide array of samples, tutorials, and documentation for those who want to learn how to developer apps for Windows 10.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-offering-free-windows-10-development-environment-vm-for-a-limited-time/