More than 20 million people live in the capital and surrounding area.
The expansion to 280-character tweets will be extended to all Twitter users except those tweeting in Chinese, Japanese and Korean.
Endurance events have captured the imagination of athletes.
They may be stuck because temperatures are starting to fall.
US Stands Alone on Paris Agreement
Scientists call these radio waves Very Low Frequency, of VLF.
Developing countries can work to close the pain gap.
The Crown Prince has become the decision-maker on military, foreign, economic and social policies.
The advertisements covered topics including race, immigration, Islam, and issues of sexual identity.
Researchers are also using ideas from origami to design a robot and a special antenna for satellites.