Binance announced that they were closing the doors for the next 12 hours. A system upgrade extension was cited as the reason.
"Due to a significant increase in users and trading activity, Binance will need to extend the System upgrade and is expected to be completed by 2PM (UTC).
Our team is working hard to complete this upgrade as quickly as possible. We will make an announcement to all users if completed ahead of schedule.
Withdrawals and trading during this period will remain suspended. We apologize for any inconvenience caused and thank you for your patience."
Hopefully they are not lying and it's not like the Japanese exchange which was hacked.