Ylinen Viipurintie road (Old Swedish Then Annen wäg ifrå Wijborg til Taffuestehwsz or Second Road from Vyborg to Hämeenlinna) is one of the three medieval main routes in Finland, following Salpausselkä to handle the connection between Häme Castle and Vyborg Castle. Due to the lack of settlement in the old times, the villages did not greatly influence the formation of the road line; rather, they were born along an existing route. In the early 15th century, in the Ylinen Viipurintie road was possible to use wagons with horses due to its good conditions and the first written mention of this road dates back to 1556. The road has been used to link the church, the market and the district and more important, as a long-distance route used by church and crown representatives, tax collectors and lawyers, merchants and traffickers, and the military.
Lahti had its first town planning after suffering a fire in 1877 and due to this the Ylinen Viipurintie road became the main street of Lahti and had changed the name to Aleksanterinkatu (Russian Emperor Alexander II). The construction of the railway 150 years ago reduced the importance of the road, but in the 1930s it was still the only public road in West Hollola that was plowed in wintertime. The road itself is still largely in use, but has undergone significant changes, for example with the construction of Highway 12. During the excavation of the center of Lahti in 1998, the road was excavated at the former Juhakkala and Mäkelä houses. The width of the road before the Lahti fire was about seven meters and there were shallow ditches on both sides. During the archaeological excavations of 2013, 30 meters of good road surface were found in the southeast corner of the market as well as a passage about six meters wide. During the period before the Lahti fire, the road seemed to run from time to time at Aleksanterinkatu, curving at Mariankatu to Torikatu.
The Salpausselkä area is about 600 km in length and 20-50 kms in width, comprising 3 ridges. Two of them are almost parallel, Salpausselkä I and II, and located across southern Finland and the third, Salpausselkä III, the shortest one, is in the SW of the country. The Salpausselkä I rises from Hankoniemi and passes through Lohja, Hyvinkää, Lahti, Kouvola and Lappeenranta north of Ladoga to Värtsillä.
The famous Salpausselkä ridges were formed during the Ice Age (11 600- 12 800) in the period known as Young Dyras which started about 12 800 and lasted for 1 200 years when the ice melting edge remained in one place for a longer period. The melting water transported the gravel and sand forming the ridges that we know nowadays.
Salpausselkä ridges stands up from other similar formations in Russia, Scandinavia and North America due to its size and height, representing a very important study in the geological literature.