Taihu, or Lake Tai, one of the largest freshwater lakes within the Yangtze River Delta, and one of the largest lakes in all of China - indeed, Lake Tai is China's third-largest freshwater lake - is situated in the southernmost part of Jiangsu Province, with part of the lake's southern boundary forming the common border between Jiangsu Province to the north and Zhejiang Province to the south. Lake Tai covers an area of some 2250 square kilometers, gives birth to a number of smaller rivers - including Suzhou Creek, which flows through first Suzhou and then Shanghai on its way to the sea - and is linked to the Grand Canal.* Lake Tai encompasses about 90 islands and islets, some no larger than the size of a backyard trampoline while others span several square miles.
The lake's northern shore is considered to be the most scenic. The city of Wuxi lies on the lake's northern shore, and it is from here - specifically, from the top of Dragon Light Pagoda in Xihui Park - that one can get the best view of the lake. Another vantage point offering an excellent view of Lake Tai is from the top of Longshan, or Mount Long ("Dragon" Mountain).
Lake Tai is probably best known for the odd-shaped limestones - a product of erosion caused by the formation of mildly acidic, and naturally occuring, carbonic acid - which stones once lay at the bottom of Lake Tai and which now adorn a number of so-called scholar gardens throughout China (Taihu rocks have also been traditionally prized as far away as Korea), in particular, the classical gardens of neighboring Suzhou (for example, Lions Grove Garden), which lies about 10 kilometers due west of Lake Tai.
The most fascinating, yet little appreciated, discovery about Lake Tai is that it appears to have been formed as the result of a meteor's impact. This explains the round-like depression in which most of the lake sits (the lake is not completely round because some parts of the underlying area where the meteor impacted might, for example, be massive bedrock, or part of the impacted area might have been loose, spongy soil with little clay content, and thus this part of the depression eventually returned to its approximate original surface height).
The latest scientific studies date the presumed impact to have occurred around 70 thousand years ago, if not earlier, possibly as early as the Late Devonian Period (the Devonian spans the period 360-415 million years ago) of the Paleozoic Era (from roughly 250-540 million years ago).** The impact crater was believed to have remained more or less dry (the fossil evidence supports this theory), except for small seasonal accumulations, until the very recent past (about 12,000 years ago), when the East China Sea flooded this part of China. Later still, the salt water receded and the lake was filled with spillover water from the Yangtze and Yellow Rivers, which grew in size, creating the delta which currently lies between these two major river systems.
The lake one sees today, though beginning to be plagued by the same pollution that one sees throughout China these days, is an exotic image dotted with numerous islets - and a few genuine islands - and is home to a multitude of birds as well as waterfowl such as the duck and the goose (duck and goose "farms" exist on the lake) as well as numerous fishes. Fruit orchards surround the lake, which has become a popular venue for city dwellers (eg., Shanghai is only 50 kilometers due east of Lake Tai) seeking to escape the summer heat. Various boating options are available on Lake Tai, but given the lake's enormous expanse, there is still room enough for everyone.
* The Grand Canal, with a total length of some 1700 kilometers, runs between the city of Hangzhou and the capital, Beijing, and is the longest man-made waterway ever conceived. Its oldest parts date from the 5th century BC, though most of the canal was dug during the Sui Dynasty (CE 581-617). Most present-day observers tend to associate monumental Chinese construction projects with the Chinese Communist Party (viz. the Three Gorges Dam project, where entire rivers were re-routed), but the Grand Canal is ample proof that the Chinese people have had a taste for grandiose engineering projects since ancient times. The rationale for the construction of the first canals was to relieve flooding, but it was quickly appreciated that this was also a way of 'bringing the mountain to Mohammad', i.e., of delivering a source of water to villagers. Canals that connected rivers opened up theretofore unknown trade and supply opportunities. The Grand Canal, one of ancient China's most impressive engineering feats alongside the construction of the Great Wall, surely served all of these purposes.
** Though it is pure speculation, it is nevertheless an intriguing notion that this meteor impact - if indeed the lake's depression was created by a meteor (which would have caused a colossal impact, given the size of the crater/ the lake) - might have been the very meteor that killed off the dinosaurs. The dinosaurs are believed to have disappeared at the end of the Cretaceous Period (spanning 65-145 million years ago, circa) of the Mesozoic Era (from 65-250 million years ago, circa), i.e., somewhere around 65 million years ago (the period previous to the Cretaceous Period was of course the Jurassic Period, which started around 200 million years ago and ended 55 million years later when the Cretaceous Period began). The time line fits (give or take - "give" in this instance - about 5 million years), and so does the fact that the area around present-day Lake Tai was dry, since it was believed that the dinosaurs perished due to a massive dust cloud that blocked the sun's radiation and plunged the earth into an instant ice age (global cooling on a massively accelerated scale, one might say!).