A scene of devastation, blanketed with grey dust, stretches into the distance in eerie silence. Walls riddled with bullets, buildings collapsing in on themselves, external walls blown away to reveal an intimate view of a bedroom or living room, streets blocked by piles of rubble.These sickening images of destruction -filmed from above by drones and shared on social media -probably best symbolize the current resurgence in urban warfare. Other images come to mind: bombed-out hospitals, children being pulled from wreckage, snipers roaming the maze of tunnels and walkways that have been blasted through the walls of now-uninhabited houses.Contrasting starkly with these often deserted urban scenes of destruction are the pictures of overpopulated camps and makeshift boats brimming over with men, women and children. City-dwellers are often forcibly evacuated or driven to flee by conflict or hardship, with no choice but to leave behind their work, their relationships and the safety of their homes.But not everyone can or wants to flee. For those who remain, life often becomes extremely dangerous and precarious when the complex fabric of urban services disintegrates: power, water and food supplies are cut off, leading to isolation, cold, darkness, illness and anxiety about what tomorrow may bring. As schools, businesses and shops close, people's future prospects disappear. Bombs -through negligence, error or criminal intent -strike people and the infrastructure they need to survive.Gaza, Sana'a, Ramadi and Aleppo have recently joined the long list of cities that have been devastated by warfare throughout history, and other cities in Syria and Iraq may soon go the same way. After an issue dealing with how war has changed, and with future editions due to cover displacement, migration and the conflict in Syria, the International Review of the Red Cross felt the need to address the subject of urban warfare, not just because of the humanitarian crises that are continuing to unfold, but because urbanization is an unstoppable trend. Tomorrow's wars will inevitably take place in urban areas, where more than half of the world's population now lives. According to the United Nations (UN) World Urbanization Prospects report, urban population growth is accelerating. Only 30% of the world's population lived in cities in 1950, but the figure was 54% in 2014 and is projected to rise to 66% in 2050. 1