In 1901, H．G．Wells, an English writer, wrote a book describing a trip to the moon．When the explorers(探险者) landed on the moon, they discovered that the moon was full of underground cities．They expressed their surprise to the 'moon people' they met．In turn, the 'moon people' expressed their surprise．'Why,' they asked, 'are you traveling to outer space when you don't even use your inner space?'
H．G．Wells could only imagine travel to the moon．In 1969, human beings really did land on the moon．People today know that there are no underground cities on the moon．However, the question that the 'moon people' asked is still an interesting one．A growing number of scientists are seriously thinking about it.
Underground systems are already in place．Many cities have underground car parks．In some cities, such as Tokyo, Seoul and Montreal, there are large underground shopping areas.
The 'Chunnel', a tunnel(隧道) connecting England and France, is now complete．But what about underground cities? Japan's Taisei Corporation is designing a network of underground systems, called 'Alice Cities'．The designers imagine using suce space for public parks and using underground space for fiats, offices, shopping, and so on．A solar dome (太阳能穹顶) would cover the whole city.
Supporters of underground development say that building down rather than building up is a good way to use the earth's space．The suce, they say, can be used for farms, parks, gardens, and wilderness．H.G．Wells's 'moon people' would agree．Would you?
The explorers in H．G．Wells's story were surprised to find that the 'moon people'