Internet
The Internet is a global wide area network that connects computer systems across the world. It includes several high-bandwidth data lines that comprise the Internet "backbone." These lines are connected to major Internet hubs that distribute data to other locations, such as web server sand ISPs.
The terms internet and World Wide Web are often used interchangeably, but they are not exactly the same thing; the internet refers to the global communication system, including hardware and infrastructure, while the web is one of the services communicated over the internet.
In order to connect to the Internet, you must have access to an Internet service provider (ISP), which acts the middleman between you and the Internet. Most ISPs offer broad band Internet access via a cable,DSL, or fiber connection. When you connect to the Internet using a public Wi-Fi signal, the Wi-Fi router is still connected to an ISP that provides Internet access. Even cellular data towers must connect to an Internet service provider to provide connected devices with access to the Internet.
How Does the internet work?
The Internet works because open standards allow every network to connect to every other network.
This is what makes it possible for anyone to create content, offer services, and sell products without requiring permission from a central authority.
When you opened your email, your email application sent a request to your email provider (for example, Gmail) through your laptop’s Network Interface Card to your Wireless Access Point (WAP) using your local WiFi. The WAP then sent the request through a wire to the local router.
The local router took that request and sent it to another router, which then sent to another router, and another router, all the way through a chain of routers until the data was transferred over one of the transatlantic communication cables to the United States.
There, it ended up at a Google data center (because you use Gmail). Google then processed your request to get any new emails that had come in since you last loaded your email. They packaged up your new, unread emails in a digital package called a “response,” and sent that package back to the same address (your laptop) that requested the updates. The response probably took different routes on the way back, but it went through the same mechanisms.
The data was transferred from the Google data center through multiple lines and reached your home router/modem, which made the data available over your home WiFi. Your laptop’s Network Interface Card received the response, sent it to your email application, and then voilà—your new emails fill up your inbox!
Security and the Internet
Installing antivirus and antimalware
Creating difficult, varied passwords that are impossible to guess.
Using a virtual private network (VPN) or, at least, a private browsing mode, such as Google Chrome's Incognito window.
Only using HTTPS
Making all social media accounts private.
Deactivating autofill.
Turning off the device's GPS.
Updating cookies so an alert is sent anytime a cookie is installed.
Logging out of accounts instead of just closing the tab or window.
Using caution with spam emails and never opening or downloading content from unknown sources.
Using caution when accessing public Wi-Fi or hotspots.
History of internet
According to wikipedia ,The Advanced Research Projects Agency (ARPA) of the United States Department of Defense funded research into time-sharing of computers in the 1960s.
Meanwhile, research into packet switching, one of the fundamental Internet technologies, started in the work of Paul Baran in the early 1960s and, independently, Donald Davies in 1965.
Packet switching was incorporated into the proposed design for the ARPANET in 1967 and other networks such as the NPL network, the Merit Network, and CYCLADES, which were developed in the late 1960s and early 1970s.