Let's take a look at what's going on in 'The World Now'.
Twitter announced Monday that its co-founder and CEO Jack Dorsey will be stepping down as the head of the company, and will be replaced by chief technology officer Parag Agrawal.
While the company added Dorsey will step down immediately, it said he would remain as a board member until Twitter's stockholder meeting next year.
The announcement came as Dorsey sent an email to staff on Monday, saying that after 16 years with the company, it was time to leave.
He also noted that Agrawal was his preferred choice for the CEO position.
The 45-year-old co-founded the social networking site in 2006.
He later became co-founder of Square in 2009, after being pushed out of the top job at Twitter before returning as the CEO in 2015.
Investors and some staff members have questioned his management style and were concerned that he was being stretched too thin by his roles at both companies.
Twitter's stock price rose 11-percent after the news of his resignation broke, before being briefly suspended.
Four people are dead, and 19 other injured, after gales slammed Istanbul on Monday.
According to the Istanbul Governor's office, one of the four casualties was a foreign national, while three of the injured are in critical condition.
Turkey's Meteorology General Directorate reported that winds of up to 130 kilometers per hour hit the city, with wind ripping off roofs and tearing down signboards, while rising sea water also flooded streets.
The intense wind also caused at least two lorries to overturn, blocking traffic on a busy highway in the city, while a clock tower in the Catalca district collapsed.
The wild weather also disrupted air traffic, with six Turkish Airlines planes unable to land in Istanbul, and instead being rerouted to Ankara and Izmir.
Officials say the strong gusts are expected to continue into Tuesday afternoon.
A little over a week after sacking Ole Gunnar Solskjaer, Manchester United on Monday named German Ralf Rangnick as its interim manager until the end of the season.
Following this period, Rangnick and the club have agreed that he will continue in a consultancy role for a further two years.
The 63-year-old has coached a number of German clubs in the past and was most recently head of sport and development at Russian Premier League side Lokomotiv Moscow, a position he will leave to take over at Old Trafford.
Former United midfielder Michael Carrick who took charge of the team during the past week, will remain in charge of the first team until Rangnick's work visa is finalized.
The club currently sits in 8th place in the English Premier League with 18 points in 13 matches.
Lee Seung-jae, Arirang News.