Finland and the Soviet Union. The land connection to Porkkala went via the Kivenlahti bridge. During the time of the naval base, part of the western coast had been evacuated, and the windows of the houses in the border villages on the Soviet side had to be covered during night time. The windows of the trains travelling through the area rented to the Soviet Union had to be covered with wooden hatches from the outside for the duration of passage through Soviet territory, and could only be reopened upon reentry to Finland. Unlike the neighbouring city of Helsinki, Espoo failed to develop a proper city centre, forming instead into an area of multiple centres. This was partly because a 1968 zoning plan where Espoo was divided into four separate areas, with the administrative centre situated in Muurala (later known as Espoon keskus), partly because most of the land in Espoo was not actually owned by the city but was instead in private ownership, directing new construction to wherever it was possible instead of using a proper zoning plan. The rather tightly populated districts of Tapiola and Leppävaara in eastern Espoo underwent attempts to separate from the city of Espoo, from two directions: on the one hand, the inhabitants of the districts wanted them to become independent municipalities, while on the other hand, the neighbouring city of Helsinki wanted to annex the districts into Helsinki. These attempts all failed and the districts remained as part of Espoo, which changed from a rural municipality first to a market town in 1963 and then to a city in 1972. The new administrative centre of the city, Espoon keskus, was built in the 1970s around the Espoo railway station and the old grey stone church in Espoo. The non-centralised nature of Espoo led to significant differences between its districts. Different parts of Espoo included the wealthy garden city district of Tapiola, large areas that still remained as countryside, and new suburbs such as Haukilahti, Karakallio and Soukka. Disagreements between different districts were common and gave Espoo a nationwide reputation of a quarrelsome municipality. The city quickly developed from a rural municipality into a fully-fledged industrial city, gaining city rights in 1972. On 1 January 1972, when Espoo gained city rights, it had a population of over 100,000, making it into the fourth-largest city in Finland at the time, after Helsinki, Turku and Tampere. Due