  Complementary to traditional approaches that focus on transceiver design for
bringing the best out of unstable, lossy fading channels, one radical
development in wireless communications that has recently emerged is to pursue a
smart radio environment by using software-defined materials or programmable
metasurfaces for establishing favourable propagation conditions. This article
portraits a vision of communication superhighways enabled by surface wave (SW)
propagation on "smart surfaces" for future smart radio environments. The
concept differs from the mainstream efforts of using passive elements on a
large surface for bouncing off radio waves intelligently towards intended user
terminals. In this vision, energy efficiency will be ultra-high, due to much
less pathloss compared to free space propagation, and the fact that SW is
inherently confined to the smart surface not only greatly simplifies the task
of interference management, but also makes possible exceptionally localized
high-speed interference-free data access. We shall outline the opportunities
and associated challenges arisen from the SW paradigm. We shall also attempt to
shed light on several key enabling technologies that make this realizable. One
important technology which will be discussed is a software-controlled fluidic
waveguiding architecture that permits dynamic creation of high-throughput data
highways.
