Complex sentence: Reaching the base takes around 12 to 14 hours of walking with the full gear (around 25 kg), this walk starts at altitude zero and end at around 1400 meters above the sea level.
Split into simpler sentences: Reaching the base takes around 12 to 14 hours of walking with full gear (around 25 kg). This walk starts at altitude zero and ends at around 1400 meters above sea level.