National Geographic December 1993

Passion Vine Butterflies { A Taste for Poison: Passion Vine Butterflies}
They float serenely amid predatory birds, harvest flowers in a set schedule, and may outlive all other butterflies. Their secret: a taste for cyanide- laced plants.
St. Petersburg, Capital of the Tsars
Monument to the worldly aspirations of its namesake ruler and his imperial successors, St. Petersburg has survived the communist years to rival Moscow as Russia’s cultural center.
The Superior Way of Life
Ocean- like Lake Superior can whip up 30- foot waves, daring those who ply its waters. Such rigors create a raw beauty – – and instill an abiding sense of community.
Glass: Capturing the Dance of Light
Some 4, 500 years ago, craftsmen in Mesopotamia fired sand, soda, and lime to create glass. Today this solid that acts like a liquid turns up in everything from fine art to fiber optics.
Himalayan Caravans
As they have for centuries, trading peoples of northwestern Nepal cross the high Himalaya in great caravans to barter for salt. Now tourism and development threaten their annual treks.