For a few days the Kossuth tér (Kossuth square) became green in front of the Parliament building. Those green poles are actually speakers. Special new technology from the U.S. which is exhibited first time in Europe. You can hear music or sound of river, birds etc. from the speakers but only if you step onto the narrow pathways. They introduced it as revolutionary technology for the future concerts and public events but to be honest I didnt find it as a big deal:)