Here's why:

* Brightness: The Orion Nebula is one of the brightest nebulae in the sky. It's visible to the naked eye under dark skies.

* Location: It's located in the constellation Orion, a very recognizable constellation visible in the winter sky.

* Dark Skies: The key is to have very dark skies, away from light pollution. The more light pollution, the harder it will be to see.

However, most other nebulae are much fainter and require at least binoculars or a telescope to be seen.

So, while you can technically see one nebula without a telescope, it's a rare feat due to needing incredibly dark skies.