Christoph Kronhagel is an architect and pioneer in Mediatecture, the transformation of the architectural space into interfaces with the digital world. In 1991 he founded ag4 in Cologne, an interdisciplinary team which helped many corporations and brands to articulate themselves digitally via media-tectonic installations. In this context ag4 developed the first transparent media facade for T-Mobile in Bonn. Many other international media facade projects followed. In 2009 he sold his ag4 shares and took a two-year break to aggregate the fundamentals of the new discipline of Mediatecture into his book of the same title. Since then he developed applications and innovations for the Digital Out of Home Market. He still manages large media facades on an international level.