National Geographic April 1989

Cry of the Loon { The Common Loon Cries for Help}
The unmistakable wail of this familiar water bird has been silenced on many North American lakes, where acid rain and other pollutants have spoiled its fishing and nesting spots. A high death rate in part of its winter range has raised new concerns about
Along the High, Wild Sierra: The John Muir Trail { The John Muir Trail: Along the High, Wild Sierra}
From the summit of Mount Whitney to the valley of the Yosemite, author- photographer Galen Rowell explores the scenic 212- mile California trail named for the outspoken turn- of- the- century conservationist who devoted his life to preserving wilderness.
Cartagena Nights
Carriage lamps and candlelight enhance the baroque facades of this historic Colombian port, whose massive battlements recall its reign as a fortress city of the Spanish Main. By Bart McDowell, with photographs by O. Lois Mazzatenta.
Living With Radiation
This invisible force has power to kill as well as cure. Charles E. Cobb, Jr. , assesses the perils and benefits, from the atom bomb and radon to radiotherapy, X rays, and the controversial issue of nuclear power. Photographs by Karen Kasmauski.
[ Kronan] — Remnants of a Mighty Warship { [Kronan: ] Remnants of a Warship’s Past}
The most powerful vessel of her day, Sweden’s Kronan sank in 1676 with a loss of 800 lives, only a week after she first saw action. Naval historians have found her remains on the floor of the Baltic – – and a microcosm of early shipboard life. By Anders