background cement city concrete decay grunge San Francisco sidewalk surface texture urban walk walkway blocks building cobblestones construction decorative England english facade faced flints frame Great Britain make making manufacture Sussex wooden architectural Asia base beginnings building-outline concrete-work dark dirty foundation-work foundational foundations groundwork hill hillside Incomplete large level levelled levels materials multilevel outlines raised remainder remaining retaining-walls rocks slope sloping solid stepped steps stone stones strength strong structure trees vegetation walls wide work bridge form highway i-35w interstate minneapolis minnesota mississippi mn pier river span break crack cracks grey old ruin ruins wall abstract architecture backdrop design gray grungy paint textures wave waves