Experts in Remote Sensing
    and Agrometeorology

"Ciudad Blanca": a major pre-colombian lost city
unveiled in Honduras

Versi�n Espa�ola

The lost city of "Ciudad Blanca"

In the eve of the 16th century, a great trading Mayan/Nahua city was flourishing in what is known today as the Mosquito Coast, in North-Eastern Honduras. This city was known by the native Central American peoples, from as far as Panama and Mexico. This city was first referred to under the double name of Xucutaco (Nahuat) and Hueitapalan (Mayan) by Hern�n Cort�s already in 1526. Cort�s himself affirms that he was informed of the existence of this city shortly after he reached the coast of the Gulf of Mexico in 1519. After Cort�s was told, Xucutaco-Hueitapalan was an impressive city, comparable in population and in wealth with Mexico/Tenochtitlan itself. After Hern�n Cort�s had to give up heading to it, the city, protected by the impenetrable rainforest of the "La Mosquitia", was ignored by the Spanish conquistadores. With time, Xucutaco-Hueitapalan was left to the jungle by its inhabitants, apparently already in the middle of the 16th century. Nevertheless, indigenous people still remembered it as the legendary White City ("Ciudad Blanca").

The region has long been a site of human occupation and has many archaeological sites. The "Instituto Hondure�o de Antropolog�a e Historia" (IHAH) is conducting studies in the region. The village Las Crucitas del R�o Aner is established over one of the largest and most impressive archaeological sites (G. Lara-Pinto and G. Hasemann, 1991: "Leyendas y arqueolog�a: � Cu�ntas ciudades blancas hay en la Mosquitia ?" In Murphy, V. (ed.), "La Reserva de la Bi�sfera del R�o Pl�tano", Ventanas Tropicales, Tegucigalpa (Honduras). pp. 16-19) . It is believed that the fabled Ciudad Blanca awaits discovery within the area. Additional archaeological research in the region may confirm the surmise that its peoples were an important link between major pre-Columbian cultures in North America and South America.

"Ciudad Blanca" unveiled by PRIVATEERS NV

The project to accurately identify and locate the ruins of Ciudad Blanca has been initiated in November 1997, with the aim to contribute to return to Honduras and to mankind a bright page of their history, and to put the site under protection of the due authorities. To do so, the project was carried out under the auspices of SEPHA, the "Sociedad para la Exploraci�n y la Protecci�n de la Historia de las Americas", between December 1997 and February 1998. The remote sensing part of the project has been kindly supported by the European Space Agency (ESA/ESRIN) in Italy, and by the National Space Development Agency of Japan (NASDA) who generously provided the satellite remote sensing data needed.

Identification and location of the lost city has been carried out using SAR images acquired by the Japanese satellite JERS-1 and by the European satellite ERS-2.
Such a task is considered a challenge, in the presence of very thick vegetation. Indeed, the radar wave does not penetrate the whole vegetation cover of a tropical forest, even at L-band.
To detect ancient ruins under very dense tropical forest and in the presence of relief, new SAR image enhancement technique had to be developed: the "Distribution-Entropy Gamma Maximum A Posteriori (DE-Gamma MAP) adaptive speckle filter (F. Yakam-Simen, E. Nezry, J. Ewing and T. Maschal, 1998: "The legendary lost city "Ciudad Blanca" found under tropical forest in Honduras, using ERS-2 and JERS-1 SAR imagery", Proceedings of SPIE, Vol.3496, pp.21-28).
Detectors based on the local spatial autocorrelation functions of both the speckle and the scene in SAR images are incorporated to these filters. They improve the restoration of the scene textural properties and of the scene structural elements, to restore the radar reflectivity without loss in spatial resolution.
Due to the nature of the targets we are interested in, and to the nature of their environment, this new speckle filter is particularly suited here as an image enhancement tool.

The archaeological site of "Las Crucitas I"

First of all, we tried to identify already known and documented sites in our SAR dataset. As an example, the site known as "Las Crucitas I" is shown below. This site is one of the many archaeological sites that compose Ciudad Blanca. The stereoscopic ERS/JERS-1 unfiltered SAR images are shown below:

Left: ERS SAR image. Right: JERS-1 SAR image. Area is shown at 20mx20m resolution.

The stereoscopic ERS-2/JERS-1 enhanced images are shown below. The features that are visible on this stereoscopic image correspond satisfactorily with the map of the site published by Lara-Pinto and Hassemann.

Processed images: DE-Gamma MAP speckle filtering using 2nd order spatial statistics.

Similarly, a number of other already documented sites, as well as numerous minor artefacts that are probable ruins scattered in a ca. 20x20 km wide area near have been identified by a careful examination of the processed images.

The new discovery at "Ciudad Blanca" (January 17, 1998)

Nevertheless, an important finding was made during this systematic examination. Covering a 3.0x3.5 km wide area in one of the denser part of the forest (close enough to Las Crucitas to be connected to the sites already documented there), the ruins of a vast complex of important structures are visible in the images. The figures shown illustrate the most interesting part of this area, including what is very probably a vast ceremonial center (Upper left quadrant of the images). The stereoscopic ERS/JERS-1 unfiltered SAR images are shown below:

Left: ERS SAR image. Right: JERS-1 SAR image. Area is shown at 20mx20m resolution.

The stereoscopic ERS/JERS-1 enhanced images are shown below:

Processed images: DE-Gamma MAP speckle filtering using 2nd order spatial statistics.

An enlargement of the important structures located in the upper-left quadrant of the previous images has been made by photo-interpretation. From the elevation map (DEM), and the shadows observed in the images, one may infer the presence of a pyramid (or a high square-shaped structure) in the north-western part of the represented area.

The results of a systematic bibliographic research conducted in Honduras, in the USA and in Europe from January 1998 to May 1998 show that this site has not been documented until now. It has probably not even been explored recently. The last report of a place structurally and contextually similar to this one in La Mosquitia dates back to 1544, when a Spanish missionary was guided there by local people...

Confirmation by SEPHA expedition (April 3, 1999)

On April 3, 1999, a SEPHA expedition, with PRIVATEERS NV team members, after efforts to evercome the obstacles set by nature and by men, reached the Ciudad Blanca area and definitely confirmed the existence of a pre-colombian city, located exactly where PRIVATEERS NV had found it.

The city covers an area as large as announced in 1998. It may have been one of the largest pre-colombian cities.

This city is likely to have been under the Chibcha cultural influence which extended from Northern Colombia to South-East Honduras in the 15th century.

Original JERS-1 data: © NASDA 1996; MITI/NASDA retains ownership of JERS-1 data;
NASDA supports PRIVATEERS NV in acquiring the satellite data (JERS-1 project #675, awarded on December 11, 1997).
Original ERS-2 data: © ESA 1996 (pilot project PE-FRNE2).
Processed images: © PRIVATEERS NV 1998.
Project partners: Ewing Data AB (Sweden) and SEPHA.