This talk addresses a promising new research direction on intelligent reflecting surfaces for the sixth generation (6G) of communication networks, which are also known as software-controlled meta-surfaces and reconfigurable
intelligent surfaces (RIS). These are semi-passive surfaces consisting of an array of meta-atoms with reconfigurable properties that can be controlled to reflect an incoming wave in a controllable way. While only the transmitter and receiver can be optimised in conventional wireless communication systems, the addition of intelligent reflecting surfaces enables optimization also of the propagation channels and, thus, the creation of smart radio environments. The main challenges to physical prototype of smart radio environments using RIS, as well as solutions to the challenges, will be addressed.