Efstathiou's recent work evolves around the concept of human intervention in the natural landscape either as a destructive force or a force of re-generation and protection. Efstathiou explores this concept through the series “Ethereal Structures”, which is comprised of oil paintings of various sizes, usually created with colours reminiscent of nature, and his signature black and grey brushstrokes. The viewers are challenged to give their own interpretation to the nature and magnitude of the human intervention suggested by the artist. One of the many inspirations for this concept is the rapid change of the urban landscape in Cyprus, and especially Limassol, where the artist is based. Within the last ten years the city centre and especially the coastal line has been experiencing a fast growth, in expense of the natural environment. The consequences and form of this human intervention has been the centre of public debate where opinions are divided.