There seemed to be a delay from the time I picked up to the time the caller responded.  He appeared to be soliciting donations for veterans.  I believe it was a scam.  You give them $100, they take $99 and use $1 to keep from being prosecuted for fraud.

Received a call from this number. Let it ring. Caller hung up, leaving no message. The CID showed the phone number plus, Springfield, VA.

Received a call from this number 703-454-0521 on 12-26-2015 @ 2:20. Let it ring. Caller hung up, leaving no message. The CID showed the phone number plus, "Springfield, VA".  One reference shows the number as unlisted.

Any legit caller will have appropriate caller ID working.  Even for a valid charity calling soliciting donations, ect...  Not Springfield, VA.  This caller is a scam artist trying to separate you from your wallet!   Also when you answer the phone or push a combination of buttons to remove your number from a so called list, YOU have just confirmed a live working number and the scammer sells your number off to another scammer.  You're now on what's called a sucker call list!  Welcome!!  There is a sucker born every minute!!  When you don't recognize a number, don't answer it.  Again any legit caller will leave a message!