Expedition is a well-prepared (equipment, food, transportation, etc.) journey through the wild nature with a specific purpose.
In our case, these are Discoveries of the Space (hard-to-reach places), Time (historical artifacts, time of endemics bloom, Golden Autumn, etc.) and Everything (everything that can be interesting for travelers). Also, it can be a narrowly specialized scientific and educational expedition - archeology, geology, botany, ethnography (festivals and holidays).