Sixteen years ago a group of Belgian cave explorers discovered a large underground room at the bottom of 400-meter-deep Tlamanictli Cave in Puebla’s Sierra Negra.
The chamber measured 400 meters long and 240 wide, but the explorers had no way of accurately estimating the room’s height, since they couldn’t see the ceiling by the feeble light of their carbide lamps.
They decided to name this vast hall La Muñeca Fea, after a cabaret they had visited in Veracruz which, in turn, was named after a popular Mexican children’s song (by Francisco Gabilondo Soler under the name Cri-Cri) which describes a doll “hidden away in a forgotten corner.”
This is the name they first gave it, but in the map they made of their survey, they simply called it La Muñeca.
The cavers’ two-dimensional survey indicated that this vast underground hall deserved a high place on the list of the world’s biggest cave rooms.
In 2011, several British cavers decided it was high time to check the accuracy of that list using the latest technology, a Lidar or 3D laser scanner, which emits laser pulses and measures how long it takes for them to be reflected back. Lidars, first used in architecture, engineering and mining, are capable of producing highly accurate 3D images of an enclosed space.
What they called The 3D Caves Project was headed by Tim Allen, Andy Eavis and Richard “Roo” Walters and they succeeded in receiving support from National Geographic magazine to survey several huge cave rooms in China.
In March of 2017, Tim Allen wrote, “Our results so far have caused some upsets. Sarawak Chamber was thought to be the largest in the world but our scanning has proven the Miaos Room in China to be significantly bigger. In Europe we also reversed the top positions again where we showed the Salle Verna to be more than twice the volume of the Carlista.”
Allen points out that their project received assistance from hundreds of other cavers. “Most of this help” he says, “has come from the host country but other individual cavers have also helped on more than one of the trips (Mark Richardson, Pete Ward and Jane Allen, for example). He gives special credit to Roo Walters, “the only one of us who can process and turn the raw data into meaningful models and statistics.”
In the course of time, the British cavers took their 3D scanner to five chambers in China, two in Borneo and to other big rooms in France, Spain, Oman, Iran, the United States and Belize.
They finally decided that La Muñeca in Puebla would be the 14th and final chamber they would visit. They were curious to accurately compare it to America’s other huge underground rooms: the Belize Chamber in Belize’s Actun Tun Kul Cave and Carlsbad Caverns’ Big Room, which — before this expedition — was claimed to be “the largest single cave chamber by volume in North America.”
Members of the 3D Cave Project and of the Belgian Alpine Speleological Group (GSAB) gathered in March in the remote hills of eastern Puebla together with other cavers from France, Iran and Mexico. In the group was Mexican cave photographer Gustavo Vela, well-known in caving circles as the author of a pictorially striking cave book entitled, Un Viaje al México Profundo (A Voyage into Deepest Mexico), and the only Mexican (in fact, the only American) ever to reach the bottom of Krubera-Voronja Cave in Abkhazia, the deepest cave in the world.
“From our base camp,” says Vela, “we drove half an hour along a spectacularly bad road and then slogged our way uphill in the intense heat for an hour and a half, weighed down by equipment and ropes. At last we came to the entrance of Tlamanictli, a wide pit with a waterfall, where we had to rig our rope as far as possible from the spray.
“A series of drops and ramps followed, until we were 400 meters below the surface and had rigged 700 meters of rope. Here a small passage brought us into La Muñeca Fea, a room that entirely swallowed the lights from our headlamps. ‘Check out the echo,’ said my compañeros, so I shouted and I heard the echo of my shout reverberate through that room for a full 13 seconds.”
The explorers then split into two groups. One began climbing the great mound of breakdown in the middle of the huge room, making their way up and around rocks as big as small houses. In the distance they could hear the sound of several waterfalls.
“When we reached the top,” says Vela, “over 100 meters above the cave floor, our friends at the bottom looked like ants and their powerful headlamps like fireflies. ‘How in the world am I ever going to photograph this enormous room?’ I kept asking myself all the rest of the day and into the night.”
Two days later, the members of the expedition reentered the cave, this time together with the British, who were carrying their 3D scanner.
“The Brits set up their Riegl VZ-400 on a tripod and turned it on,” says Vela. “The machine whirred and the head turned round and round, taking 400,000 measurements per second of everything within a maximum 400-meter range. Then they picked it up and set it up in a new location. The room was so big that they had to repeat this operation 52 times. It took them two full eight-hour days to do this.”
All this gave Gustavo Vela plenty of time to try to get a picture of the room that seemed impossible to photograph. He had nine assistants, ready to point electronic flashes wherever he directed, and four walkie-talkies to communicate with them . . . which, he says, “was no easy task, as some of them spoke English, some French and very few Spanish.”
In spite of all the difficulties, Vela succeeded in taking several exceptional time exposures inside La Muñeca Fea.
As for the Brits, says Vela, “they recorded so much data that it took them 48 hours just to download it into a computer with an exceptionally large memory. It then took this computer two full weeks to piece together all that data in order to produce the dramatic rotating 3D image which is on YouTube for all the world to see.”
The cave room turned out to be 396 meters long, 242 wide and 225 high, twice the height the 1999 explorers had imagined, resulting in a volume of 5.9 million cubic meters, big enough, says Gustavo Vela, to hold Mexico City’s huge Aztec Stadium six times.
That makes Muñeca Fea the fourth largest known cave room in the world and the largest so far found in the Americas. Both Carlsbad and Belize chambers have volumes less than one million cubic meters so, says Tim Allen, La Muñeca is more of the “big daddy” than the “baby doll” that a translation of the name would suggest.
The five biggest underground rooms in the world are:
1. Miao Room, China
2. Sarawak Chamber, Borneo
3. Cloud Ladder Hall, China
4. Salón La Muñeca Fea, Mexico
5. Hong Meigui Chamber, China
The writer has lived near Guadalajara, Jalisco, for 31 years, and is the author of “A Guide to West Mexico’s Guachimontones and Surrounding Area” and co-author of “Outdoors in Western Mexico.” More of his writing can be found on his website.