The San Francisco Exploratorium, that epicenter of hands-on science, is exploring Polynesian navigation. At Reading Sea and Sky, a new exhibit in the Exploratorium's Webcast Studio, visitors step in and out of time and place.

A giant star compass representing those used in ancient navigation techniques extends across the floor — at times submerged beneath video footage of waves projected from above. Visual poems of the islands are screened continuously accompanied by stories recorded by the Exploratorium team during a trip to Hawaii.

The team also has created Never Lost, a companion Web site to accompany the installation.

Reading Sea and Sky is through May 9 and the exhibit is included in the Exploratorium's admission. Never Lost will be available in Hawaiian and English and is set to launch on May 1.

Exploratorium hours: 10 a.m. to 5 p.m. daily, closed Mondays. $15, adults; $12, students, seniors and ages 13-17. http://exploratorium.edu.imiloahawaii.org

PERU

LEGENDARY MACHU PICCHU REOPENS

Peru reopened Machu Picchu earlier this month, allowing tourists to enter the 15th century Inca citadel for the first time in nine weeks. Flash flooding had destroyed parts of the railway between Cuzco and Machu Picchu.

Known as Old Peak in Quechua, Machu Picchu, a world heritage site, sits on a remote mountain ridge 50 miles north-west of Cuzco.

Believed to have been built by the Incas around A.D. 1400, it was abandoned when Spanish conquistadores carved up the empire, possibly because smallpox had wiped out the indigenous population.

According to the Tourism Observatory of Peru, about 858,000 visit Machu Picchu each year, which tops the Galapagos Islands, Argentine glaciers and Aztec and Maya ruins as Latin America's most popular attraction.

In January, heavy rains and landslides reportedly killed at least five people, washed away the rail link and stranded thousands in the town of Aguas Calientes, at the foot of the ruins.

AIR TRAVEL

FLIERS CAN LEAVE IPADS IN BAGS AT SECURITY CHECKPOINTS

Apple's iPad tablet is friendlier than a traditional laptop when it comes to airport security. Because it's small and people who carry the device often don't have bulky accessories like plugs and external drives that clutter the screening image the Transportation Security Administration said generally you should not need to remove your iPad from your bag.

Laptops still may have to be put on the security conveyor belt. Checkpoint-friendly laptop bags can be found on www.eBags.com.

— Associated Press