Ключевые слова: analysis, arc, arch, architecture, astronomy, axis, bent, building, celestial, change, curve, destinations, discovery, engineering, equator, europe, exploration, futuristic, germany, halde, heap, herten, hoheward, horizon, horizonobservatory, landmark, landscape, meridian, modern, monument, nrw, observation, observatory, orbit, orbiting, outdoors, peak, people, pipe, research, ruhr, science, sky, space, steel, time, travel, tube,