The given maps illustrate a number of changes taking place in a city between 1950 and present day.
Overall, the most significant modification after nearly 70 years is the expansion of residential area. In addition, the river and the airport witness no changes in their position.
It can be noticed that the population of the city now is ten times higher than that in 1950, which is also directly proportional to the size of residential area after 70 years. Besides, the business district in the middle of the city has been expanded to the South. At present, a new lake along the river has also appeared.
A new small bridge has been erected in the East of the river, which was opposite the construction of a dam. Although the airport witnesses no changes in the position, its size has been increased nearly three-fold. To the South of the river, the government building has been reduced in size, and a bigger one has been built in the bottom of the city. 
The  
given
 maps illustrate a number of  
changes
 taking place in a city between 1950 and present day. 
Overall
, the most significant modification after  
nearly
 70 years is the expansion of residential area.  
In addition
, the  
river
 and the airport witness no  
changes
 in their position.
It can  
be noticed
 that the population of the city  
now
 is ten times higher than that in 1950, which is  
also
  directly
 proportional to the size of residential area after 70 years.  
Besides
, the business district in the middle of the city has  
been expanded
 to the South. At present, a new lake along the  
river
 has  
also
 appeared.
A new  
small
 bridge has  
been erected
 in the East of the  
river
, which was opposite the construction of a dam. Although the airport witnesses no  
changes
 in the position, its size has  
been increased
  nearly
 three-fold. To the South of the  
river
, the  
government
 building has been  
reduced
 in size, and a bigger one has  
been built
 in the bottom of the city.