Historical Crude Oil Prices

This graph, taken from BP’s 2015 “Statistical Review of World Energy” report, shows crude oil prices, measured in US dollars per barrel, from 1861 to 2014.

What trends do you see in the ways that crude oil prices have fluctuated in response to world events? 

Citation: 
BP Statistical Review of World Energy, 64th edition, June 2015 (https://www.bp.com/content/dam/bp-country/es_es/spain/documents/downloads/PDF/bp-statistical-review-of-world-energy-2015-full-report.pdf)
Library Item date: 
2015