Just following on from Byrd's post,
Here's some good detective work by actual anthropologists and archaeologists using declassified IKONOS spy satellite images of Costa Rica.
The story below gives a very good basic explanation of how the ancient pathways were discovered.
abcnews.go.com - Page 1

For hundreds of years, the people who lived near the violent Arenal volcano in Costa Rica followed the same pathway, straight through the forest
from their village to their cemetery, over and over again.
Beginning more than 2,500 years ago, the footprints of those early sojourners slowly carved a rut into the soil.
Now, all these years later, scientists are puzzled and amazed by an ancient pathway, long buried by volcanic ash and vegetation that has resurfaced
again in satellite images from space.
abcnews.go.com - Page 2

What's amazing, Sheets says, is that this technology should work at all in the Costa Rican rain forest. Satellite images have been used to find
ancient human artifacts buried beneath the sands of the Sahara Desert of north Africa and ancient roads near Rome, where conditions are dry enough and
vegetation is sparse enough to make it feasible. But no one was sure it would work in the rain forest.
abcnews.go.com - Page 3
A related article on the use of satelite imaging and google earth in the discovery of ancient ruins. Due to the expense of aerial and satelite imagery
google earth really is a viable option for archaeologists, they just don't release their findings to UFO sites, preferring instead Peer review, damn
silly of them really.
www.cosmosmagazine.com

When NASA's only archaeologist, Tom Sever, looked at an infrared satellite image of a Mayan city in Guatemala, he was intrigued to see the
vegetation around the buildings showed up as much brighter than the vegetation in other areas
.....snip.....Payson Sheets, a professor of
archaeology at the University of Colorado, has directed the Arenal Research Project in northwestern Costa Rica since the 1980s.

But then, as the story goes, an Italian computer programmer, Luca Mori, turned its use to archaeology. Using Google Earth, he found signs of a
Roman villa buried beneath a riverbed. He contacted experts, who decided to excavate.

Within a few hours on Google Earth, Madry was able to locate 101 features in an area covering 1,440 square kilometres in Central France. These
features represented Iron Age, Medieval and Gallo-Roman sites.
"I have found a very large number of sites using Google Earth from my office here in the U.S.. I was quite surprised at this, and have now given many
different short courses in the U.S. and Europe for archaeologists on how to use Google Earth in their work," Madry said
Slightly off topic, but i remembered reading about this discovery at Lake Titicaca many years ago and this thread reminded me to see if i could find
it again.
Peru finds pre-Inca ruins beneath Lake Titicaca

LIMA, Peru (Reuters) - Peruvian divers have found pre-Inca stairways, ramps and walls beneath the waters of Lake Titicaca, but experts say
the discoveries are not the remains of a legendary lost city.

"There are studies that show that the lake used to be ... around 66 to 98 feet (20 to 30 metres) lower, and that was where ancient Peruvians
built," he said.

Poking 10 feet (3 metres) out of the middle of the lake, the team also found what they dubbed the "mystery rock" that measures 66 feet (20
metres) across.
A stone statue in the shape of a llama was found on the rock,
Some related links:
news.bbc.co.uk

The holy temple measures 200m by 50m (660ft by 160ft) almost twice the size of an average football pitch.
More than 200 dives were made into the lake, to depths of as much as 30m (100ft), to record the ruins on film.
The explorers found the temple after following a submerged road, in an area of the lake not far from Copacabana town
www.sacred-destinations.com.
Some beautiful photo's and tourist information.
If anyone has any links to more recent information regarding the temple and ruins it would be much appreciated, most of what i have been able to find
is at least 5 years old.
Once again sorry for the slightly off topic post.
mojo