Ключевые слова: 1, 3d, 51, background, banner, building, business, card, celebration, commercial, concept, construction, day, design, engineer, engineering, equipment, fist, freedom, graphic, greeting, hammer, happy, holiday, icon, illustration, industrial, industry, international, job, labor, labor day, labour, man, may, may 1, may 1st, national, occupation, poster, professional, safety, sky, symbol, tool, tower, woman, work, worker, wrench,