Not everything on the web will show up in a list of search results on Google or Bing; there are numerous places that the sites' web crawlers cannot access.

To explore the invisible web, you need to use specialist search engines. Here are our top 12 services to perform a deep internet search.

What Is the Invisible Web?

Before we begin, let's establish what does the term "invisible web" refer to? Simply, it's a catch-all term for online content that will not appear in search results or web directories.

There is no official data available, but most experts agree that the invisible web is several times larger than the visible web. Given that Google, Amazon, Microsoft, and Facebook alone store more than 1,200 petabytes between them, the numbers quickly become mind-boggling.

The content on the invisible web can be roughly divided into the deep web and the dark web.

The Deep Web

The deep web is made up of content that typically needs some form of accreditation to access. For example, library databases, email inboxes, personal records (financial, academic, health, and legal), cloud storage drives, company intranets, etc.

If you have the correct details, you can access the content through a regular web browser.

The Dark Web

The dark web is a subsection of the deep web. You need to use a dedicated browser (such as Tor) to access dark web content. It's more anonymous than the regular web and is thus often the home of illegal activities such as drug and weapon sales.

However, not everything on the dark web is illegal. Some of the best dark web websites are just versions of regular sites, but are hidden to enable users in totalitarian regimes to access them.

1. Pipl

Pipl brands itself as the world's largest people search engine. Unlike Google, Pipl can interact with searchable databases, member directories, court records, and other deep internet search content to offer you a detailed snapshot of a person. You can also use Pipl to deep search yourself.

2. The Wayback Machine

The WayBack Machine website

Regular search engines only provide results from the most recent version of a website that's available.

The Wayback Machine is different. It has copies of more than 361 billion web pages on its servers, allowing you to search for content that's no longer available on the visible web. It's also a handy site for viewing old versions of any website.

3. The WWW Virtual Library

The WWW Virtual Library is the oldest catalog on the web. It was started by Tim Berners-Lee, the creator of the World Wide Web, back in 1991.

Volunteers compile the list of links by hand, thus creating a high-quality index of deep web content across dozens of categories.

4. DuckDuckGo

DuckDuckGo search engine home page

DuckDuckGo is well-known as one of the best private search engines for the visible web and offers one of the best privacy-focused smartphone browsers. But did you know the company also offers an onion site that lets you explore the dark web?

Even the regular search engine offers more deep web content than Google. It pools results from more than 500 standalone search tools to find its results. If you pair the regular DuckDuckGo engine with the Onion version, you can perform an entire web search.

The Onion site can be found at https://duckduckgogg42xjoc72x3sjasowoarfbgcmvfimaftt6twagswzczad.onion/.

5. USA.gov

www.usa.gov website homepage

The amount of content on USA.gov is seriously impressive. It's a portal to all the public material you need on every federal agency and state, local, or tribal government.

You will also find information about government jobs, loans, grants, taxes, and a whole lot more. Most of the information on the site will not appear on Google.

6. Directory of Open Access Journals

Drectory of Open Access Journals' website

The Directory of Open Access Journals is a deep internet search engine that provides access to academic papers. The papers are available to anyone without charge.

The current repository has over 19,000 journals with over 8.9 million articles across all subjects. Although you can easily find free articles on Google Scholar, and it can access some of the information, we think that the DOAJ is a better research tool.

7. SearX

If you are looking for a dark web search engine that also gets data from the visible web, check out Searx. The site has an Onion domain name, so is not accessible through a standard web browser. To load it, open a dark web browser such as Tor and paste http://searx3aolosaf3urwnhpynlhuokqsgz47si4pzz5hvb7uuzyjncl2tid.onion/ into the address bar.

It pulls data from different search engines, so it opens you to a world of endless possibilities. If it exists, this search engine can probably find it.

8. Elephind

Elephind.com historical newspaper archive

Elephind aims to provide a single portal to all the historical newspapers of the world. It's a fantastic resource for researchers—especially family historians, genealogists, and students.

Many of the newspapers on the site are exclusively on the deep web; they will not show up on Google. At the time of writing, over 3.6 million newspapers are available.

9. Torch

As one of the oldest deep web search engines, Torch is one of the best. Torch prides itself on not censoring any search results, and it scours the deep web every day for new publicly available Onion websites on the Tor network.

There are over a million documents indexed by the search engine as of writing. To access Torch, copy and paste the following link in Tor: http://xmh57jrknzkhv6y3ls3ubitzfqnkrwxhopf5aygthi7d6rplyvk3noyd.onion/

10. Ahmia

Ahmia deep web search engine home page

Ahmia is a dark web search engine. But there's a twist—it is one of the few dark web search engines that is available on the regular web.

Of course, any links and results will not be openable unless you have the Tor browser installed on your computer. However, it's still a great way to get a taste of what's available on the dark web without exposing yourself to the inherent risks of using the dark web.

11. WorldCat

How do you know which books that the different local libraries in your area have in stock? Going through each library's site individually is time-consuming and potentially error-prone.

Instead, check out WorldCat. This deep internet search engine has two billion indexed items from libraries around the world, including many links that are only typically available with a database search.

12. Project Gutenberg

project gutenberg

If you search for obscure copyright-free ebooks on Google, you'll have to click through several pages to find a result that provides a download link.

Project Gutenberg offers over 60,000 free ebooks for you to check out and download. It provides variable formats and also provides you with a list of similar books to download. It's undoubtedly one of the best sites to download ebooks for free.

Learn More About the Invisible Web

The 12 search engines we have introduced you to should provide a solid base on which to start your hunt for content. Sadly, one of the most famous deep search engines from the past, Deeppeep, no longer exists, but all the sites in the article can help to recreate the lost features.

Want to explore the dark web more? There are a host of other dedicated search engines you can use.