Nothing lasts forever. Towers crumble, empires fall, and the best businesses in the world will eventually go belly up. The Dow Jones Industrial Average index held 20 names 100 years ago. None of those companies sits on the expanded 30-ticker Dow Jones scorecard today. Zero. None at all.

So when I say that I'll hold the following three stocks forever, please understand that I mean "forever for all practical purposes." Eternity is much too long of an investing horizon, even for truly long-term investors whose favorite holding period is "forever."

That being said, it would take a lot to take these three stocks away from me. At the very least, these will probably be the last stocks I sell when the time comes to take money out of my retirement accounts rather than adding to them.

Three stacks of gold coins, stacked on a calendar.

Image source: Getty Images.

Netflix

The streaming media veteran has been good to me. Netflix (NASDAQ:NFLX) is the largest holding in my portfolio, by far. The shares I added in the wake of the Qwikster crisis in 2011 have posted a 2,600% return so far. My original buy-in has delivered an 8,000% gain since the summer of 2006.

I don't expect anything near those gains in the next 10 or 20 years. Instead, I expect this high-growth investment to mature into a fantastic cash machine in the 2020s. The returns may be less dramatic in the long run, but we're watching the early days of a budding entertainment giant on a global scale.

Netflix is, in fact, one of the best buys on the market right now. If anything, I'm tempted to add a few more shares to my stockpile at these attractive prices.

Walt Disney

I don't really have to explain what Walt Disney (NYSE:DIS) is, do I? The entertainment conglomerate is based on a culture-defining content portfolio that stretches back to the early days of Hollywood's history -- Mickey Mouse has been around since 1928 and Snow White hit the silver screen in glorious Technicolor in 1937. When adjusted for inflation, Snow White remains one of the 10 biggest money-makers ever, and the three movies that came closest to knocking the princess down a peg over the past decade all came from Disney-owned franchises.

The House of Mouse uses these iconic stories and characters as the foundation for a massive entertainment empire, spanning from theme parks and hotels to syndicated TV series and Disney-licensed lunch boxes. When hunting for new ways to exploit a well-known fictional character, this company leaves no stone unturned.

The House of Mouse isn't afraid to change things up in order to stay relevant in ever-changing cultural and business environments. Massive buyouts are part and parcel of the Disney story, ranging from cable networks in the 1990s to Fox in 2019. The three mega-hits I referred to a moment ago all came from acquired franchises, including two of Marvel's Avengers titles and one installment of the Star Wars saga.

This is the kind of stock you can buy today and stick in your pillowcase (or give to your grandkids) and not lose a minute of sleep as Disney builds shareholder value over the next several decades.

Alphabet

If I could only own one stock right now, and that single ticker would remain the only holding in my portfolio forever, Google parent Alphabet (NASDAQ:GOOG) (NASDAQ:GOOGL) gets that nod.

This company marries a massive revenue base from its Google-branded operations to an incredibly flexible business structure. Google might not be much of a business 20 years from now, but Alphabet will have replaced that fading operation with a plethora of different ideas. Current experiments range from self-driving cars and energy storage to drone-powered shipping and delivery services and cutting-edge medical research.

Any of these alternative businesses may eventually dwarf Google's money-making stature. I'm betting that several of Alphabet's evolving ideas will reach that status. We're witnessing the early days of a sector-spanning conglomerate that should be able to crush the market for many decades to come.

I don't recommend anchoring your entire investment strategy on a single stock, but this is the only company I would trust in a scenario like that. That also makes Alphabet a fantastic cornerstone of a more diversified portfolio, of course.