What’s Up

Tiffany diamonds, Portugal and “Great Britons”

Some Rock

Set in a 1960s brooch, this 128.54-carat gem is one of the world's largest yellow diamonds. On loan to the Natural History Museum until September 23, Tiffany & Co.'s signature stone has only been worn twice—once by Audrey Hepburn to promote, yes, Breakfast at Tiffany's.

Friends and Neighbors

Poet and photographer Ellis Marsalis III, of the famous jazz family, spent a decade chronicling life in his working-class Baltimore neighborhood. Selections from his 2004 book, thaBloc, are on view at the Anacostia Community Museum through August 12.

O Mundo Inteiro

"The whole world?" Almost. In the 16th century, Portugal built a trade network that stretched from Brazil to Japan. At the Sackler Gallery and African Art Museum until September 16, some 250 maps, paintings and artifacts revisit this commercial empire. (Read more about Portugal's "Global Empire.")

Across the Pond

Artist George Frederic Watts' marriage to actress Ellen Terry, 30 years his junior, lasted less than a year, but it resulted in this c. 1864 oil. It's one of 60 paintings and photographs of "Great Britons" that the U.K.'s National Portrait Gallery lends its U.S. counterpart until September 3.

Intelligent Design

Given the chance to rummage through the Cooper-Hewitt's collections, a team from international design firm IDEO (co-creator of the modern computer mouse) selected more than 30 innovative objects, including this 1944 child's chair by modernists Charles and Ray Eames. On view until January 20.

Get the latest Travel & Culture stories in your inbox.