The Soviet Union at its largest size in 1991, with , was the world's biggest country. Covering a sixth of the world's lived in land, its size was comparable to North America's. The western part (in Europe) accounted for a quarter of the country's area, and was the country's cultural and economic center. The eastern part (in Asia) extended to the Pacific Ocean to the east and Afghanistan to the south, and was much less lived in than the western part. It was over across (11 time zones) and almost north to south. Its five climatic (different weather, temperature, humidity and atmospheric pressure) zones were tundra, taiga, steppes, desert, and mountains.