Two places come to mind immediately;
The soda lakes of Tanzania
The soda lakes of Tanzania are quite uncomfortable places for humans to be, and ultimately they fill the brief of 'somewhat' hostile to human life. But, they also look the part when you think of an alien landscape.
These lakes of soda ash are pink in colour and extremely alkaline, meaning that humans will find them quite uncomfortable to be around even with basic protective clothing. As such, there are no humans around these although you will find flamingos at certain times of the year as they come here to raise their chicks far away from where anything even remotely close to a predator is going to come.
Coober Pedy, Australia
Second, there's a place in Australia that looks like an alien landscape for an arid desert planet that was actually used as the location for shooting the original Pitch Black movie with Vin Diesel - Coober Pedy.
Famous as an area rich in opals and for being so hot that many of the homes are literally carved out underground to escape the heat, there are areas in the surrounds that can give a desolate feel and the sheer heat and lack of water (and the subsequent cold at night) can make this feel like a very uncomfortable place. Its isolation also fits the brief; this is not a place you want to get lost in and not have anyone know you're missing. People die in the Australian Outback all the time through not being prepared for the harsh conditions and the sheer size of the place.
There are bound to be others as well but these are useful because they lack a lot of vegetation. For most humans, seeing a tree or a bush or a flower etc. that they recognise is going to be the killer blow to your illusion. They're going to expect plants to look VERY different to what they know on Earth, so any place with vegetation is going to be hard for your punters to accept as alien. These two places on the other hand don't have a lot of vegetation, or water for that matter, making it an easier sell. Ultimately though, how well you can maintain the illusion is not just dependent on how exotic a location you can find, but how well read your punters are. In today's world, it's going to be a lot harder than it would have been (say) 100 years ago when knowledge was locked in Encyclopaediae that you had to know what you were looking for in order to find things out in them. With the advent of the internet and mass media, the chances of at least one of your punters knowing that they are still on Earth is higher, just simply because they have access to more information now than ever before.