Consider this: you are the proprietor of a movie theater in the cute northern Dutch town of Groningen. There happens to be a room in the back of your premises, behind the movie screens, which can only be entered from a separate doorway on the other side of the building. (From personal experience, I know this is the case in many theaters.)
Enter squatter "Pino", who happens to be looking for a new place to live. Never mind that pigeons occupy the room, or that you have stored some items there. And never mind there is no heat either; Pino will just bring his own gas heater. It's hardly Buckingham Palace, but he has just found himself a great home.
Isn't that a matter of trespassing? Get yourself a gun, or a baseball bat, and kick the guy out of your building? Or call the police, who will do the same for you? No. Not in the Netherlands, where one is allowed to occupy someone else's real estate once it has been empty for at least a year. You might pay a visit to the room every once and a while to get some things out of it, or to store some, but judging from the pigeons' droppings all over the place, it has been empty all along. Period.
Since the police are of no use to you, you decide to have the fire department declare that the new situation poses a safety risk to your building. After all, the place was never meant to function as living space. But no, the fire department argues there is no problem here whatsoever. And so you have little choice but to allow Pino to live in your building, having him pay zero rent and perhaps steal your electricity as well.
Then, of course, the inevitable happens. Pino's little heater turns out not to be as safe as the fire department claimed, or he falls asleep leaving the candles burn. Either way, he sets the room on fire (NL). Pino himself is able to escape the flames, but you can be sure at least one of three matinee shows of the next day will be canceled. The brand-new movie screen is ruined, and there is water all over the place. Repairing the damage done to your property might cost you tens of thousands of euros, if not hundreds of thousands.
And the best is yet to come. Your insurance company had researched the situation as well, and had concluded all along that it would not be safe for Pino to live in the room. As a result, you might not receive one single dime for the damage done to your property. So while you have no legal means to protect it from being taken by squatters, you have no means to insure it against their destructive way of life either.
Your only options are to file a lawsuit against the insurance company, the fire department, and/or Pino. You can be fairly sure the latter is unemployed and lives off of an 800-euro government allowance, so don't expect to get compensated by the person who started the dramatic event in the first place...
Welcome to the Netherlands.