美国有线新闻 CNN 吉萨金字塔内部竟藏两个密室 秘鲁上万极度濒危青蛙死亡（在线收听）

Stories from Egypt and Peru start things off today.

Our first report is from North Africa. Scientists examining the Great Pyramid of Giza think they might have discovered two hidden rooms in the structure. The Great Pyramid is the largest of Giza's three pyramids. Researchers believe it was built more than 4,500 years ago.

Scientists have been scanning the pyramid, kind of like taking x-rays and heat scans of it, and they detected what could be unknown cavities or rooms inside the structure. More tests are needed before researchers can be sure these rooms are significant. At this point, they only add to the mysteries of the Great Pyramid.

Another mystery is troubling officials in South America. Thousands of critically endangered frogs living near Peru's Lake Titicaca have died and no one knows why. The Titicaca water frog has struggled in recent decades. It's been overhunted for food, it's lost parts of its habitat, exotic trout have been eaten the frog's tadpoles.

But investigators are trying to find out what's causing so many of them to suddenly turn up dead. Some residents of the area think that raw sewage coming from a nearby city might be killing the frog.