Ключевые слова: agriculture, america, beautiful, beauty, clouds, cloudscape, colorado, crude oil, dark, dawn, denver, dramatic sky, drill, dusk, electricity, energy, environment, equipment, field, flammable liquid, fossil fuel, fuel and power generation, gas, gasoline, geology, global business, grassland, historical reenactment, horsehead pumps, industry, lowland, nature, orange, people, petroleum, power, prairie, reenactment, rocky mountain, rural scene, scenics, shrubland, sky, sun, sunset, technology, united states, us, usa, yellow,