postage stamps

The 1868 One-cent “Z” Grill
America’s Most Valuable Postage Stamp to Auction with $5 million Estimate
Siegel Auction Galleries of New York City is to offer the William H.
The Mulready letter-sheet combined with a Penny Black stamp
First Piece of Mail Sent Using Penny Black Stamp Comes to Auction with $2.5m Estimate
Sotheby’s will offer a one-of-a-kind item linked to the history of modern mass communication: the earliest posted envelope using a prepaid stamp.