Torre Edimburgo, for diplomatic/hotel purposes, is still under construction but that´s the finished façade.
El Parque de Pies Descalzos (Barefoot Park), a therapeutic reflexology experience where you can wet your feet in warm water, walk through sand and relax.
Edificio EPM (Empresas Públicas de Medellín). The public works building of Medellín is extremely efficient: it produces its own ventilation, treats its own water, and has floors organized by the amount of traffic (for example, conference rooms on the bottom floors, more exclusive offices at the top).
Water treatment doubles as a nice moat.
Weird uploading error, but I like it! You can catch a glance of the ventilation system at the top.