May 21-July 18

Bhutan, a land famous for monasteries, historical architecture and picturesque mountains at the eastern end of the Himalayas, is often known as the happiest country in Asia.

To celebrate 30 years of diplomatic relations between Bhutan and Japan and perhaps reveal why it rates so high in happiness, the Ueno Royal Museum is hosting a showcase of rare Bhutan artifacts. More than 140 pieces will be on display for the first time in Japan, including a Bhutanitis ludlowi swallowtail butterfly specimen. The butterfly is endemic to Bhutan and its first sighting in 80 years was in 2011, after which it became a national symbol.

The Ueno Royal Museum; 1-2 Ueno-koen, Taito-ku, Tokyo. Ueno Stn. 10 a.m.-5 p.m. ¥1,400. 0570-00-3337. www.fujitv.co.jp/events/bhutan