How were towns and cities in the fifteenth century different from the Middle Ages?

During the Middle Ages, towns and cities were usually small in population.  For example, the population of London reached just above 50,000 by the end of the Middle Ages.  Many towns and other cities were even smaller.
Death and disease were common in the Middle Ages and this also caused populations to fluctuate.  Poor disposal of human waste led to diseases.  Chamber pots were often dumped out of windows and onto the streets.  When it rained, the waters would wash the waste into rivers.  During periods of less rain and during the winter, waste lingered in the streets.  The bubonic plague killed millions of people throughout Europe during the Middle Ages.  Statistics say that approximately 60% of people in Europe perished from the plague.
Most structures in towns and cities during the Middle Ages were small.  Typically, churches and guild halls were the largest structures in a Middle Ages town.  Merchants who sold the same types of goods or provided the similar types of services tended to set up shop on the same street.  Many streets were named after a particular type of trade.  Fire sometimes destroyed cities and towns, as houses were constructed out of wood.
Population increased in the 15th century.  The population of London doubled and even tripled during the 1400s.  There were some developments in the study of medicine, and less death caused by the bubonic plague.  More people moved to cities from the countryside.
As cities grew and became more sprawling, more structures were built.  Most houses remained small.  More churches and other structures were constructed.  Trade increased as explorers and merchants began sailing farther distances.