Excellent example of an over-polished die! That Cent is known as the Floating Roof variety. You can find then on very early 1970's Cents.
you can Google Floating Roof Cent and see webpages on the subject. Some even taking you to threads here on CoinTalk! Quote "There are specimens in which overpolishing has removed the details of the soffit below the roof. This is called a "Floating Roof". The creation of these varieties is not by design, nor is it an error. It is a production anomaly and the level of quality is often subjective and open to debate. Nonetheless, some of these are recognized minor die varieties. Fivas and Stanton attribute the 1969-D as FS-901 in The Cherrypicker's Guide and it has been recognized by PCGS, with top grade specimens selling in the hundreds. I understand that PCGS no longer certifies these coins." Closed quote
