The scientific and technological exploration of three-dimensional magnetic nanostructures is an emerging research field with exciting novel physical phenomena, originating from the increased complexity in spin textures, topology, and frustration in three dimensions. Tailored three-dimensional nanomagnetic structures, including in artificial spin ice systems or magnonics will enable novel applications in magnetic sensor and information processing technologies with improved energy efficiency, processing speed, functionalities, and miniaturization of future spintronic devices.