context: Yemen's land area is about 528,000 km². The capital is or and can be divided geographically into four regions. It is a region of the Red Sea coast, the western mountains, the eastern mountains, and the northern Ruhl Al-Hali Desert. The Red Sea coast, called Tihama, is very dry, and rivers flowing in the mountains are hard to see, and exist in the form of wadi or groundwater. Western mountains are terraced because of heavy rainfall. Sorghum dominates and fruits such as cotton and mango are grown. The temperature difference between the day and night is great. The eastern part is 2,000m above sea level, and the temperature difference is larger than the western part. The temperature difference between daytime 30 ℃ and nighttime 0 ℃ is also shown. In the eastern part, barley and wheat are grown. There are Bedouin nomads in the Rual-Al-Hali Desert, but they do only camel nomads. On the coastal plains of the Gulf of Aden, hydroponic cultivation is used. The temperature is high on the Red Sea coast and the central highlands are comfortable. In the central part, rainfall is 400 ~ 1,000mm per year. The Red Sea coastal plain has a high temperature and high humidity of 40 ~ 50 ℃.
question: Where is Yemen's capital?
answers.text: or