Ключевые слова: architecture, background, building, business, business travel airport, city, close up, concept, design, dirty, doors, dulles international airport, elevator, empty, escalator, escalators, exit sign, glass, going up steps, hall, indoor, interior, mall, metal, metro, modern, no people, office, old, outdoor, overhead view, perspective, public, stair, staircase, stairs, stairway, station, steel, steps concept, steps to success, technology, terminals, transport, transportation, travel, up, urban, wall, washington dc,