Ever been walking somewhere and catch the scent of something that immediately brings you back to specific time, place, or person? Every time I catch the scent of a perfume I used when I was younger tons of memories of pastimes come raising back. Why is this? What connects scents with memories?
According to body odd.nbc.news.com, after a smell enters the nose, it goes through the cranial nerve through the olfactory bulb. Here it accesses the amygdala, which plays a role in emotional memories. The amygdala and the olfactory bulb are one reason for the cause of nostalgia. Dr.Ken Heilman says that scents do bring back memories, because unlike words that bring back thinking parts of the brain, they bring back the emotional parts of a memory. So this led to wonder if memories that rely on smells are more reliable than other senses? After some research, I quickly learned that this is most definitely true, with the exception of those who have heightened vision or hearing due to problems with smelling. This is the exact reason as to why Canines, who have a heightened sense of smell, work closely with the police force. Next time you catch the smell of something that brings back a pleasurable memory, enjoy the nostalgia. 
This is an awesome post! I have experienced this so many times before. Whenever I smell something that I have smelled before, I always think of a memory. There have been many studies conducted to try and figure out why scents are linked to our memory. Psychologists have found scents to be useful in therapy. Often times the brain might block out a certain memory for whatever reason. But if the patient smells a familiar scent that links to that memory, they could remember it. I found this to be very interesting. http://psychology.about.com/od/memory/ss/ten-facts-about-memory_8.htm