Nowadays, most people use several websites on a daily basis for various purposes like social networking, shopping, reading news, etc. which shows the significance of these websites in our lives. Due to this phenomenon, businesses can make a lot of profit by designing high quality websites to attract more people. An important aspect of a good website is its page load time. There has been a lot of studies which analyzed this aspect of the websites from different perspectives. In this thesis, we characterize and examine the complexity of a wide range of popular websites in order to discover the trends in their complexity metrics, like their number, size and type of the objects and number and type of the contacted servers for delivering the objects, over the past six year. Moreover, we analyze the correlation between these metrics and the page load times.