Complex sentence: Below the fortress-like structure lies the gold vault lined with granite walls and protected by a blast-proof door weighing 22 tonsmembers of the Depository staff must dial separate combinations known only to them.
Split into simpler sentences: Below the fortress-like structure lies the gold vault lined with granite walls and protected by a blast-proof door weighing 22 tons. Several members of the Depository staff must dial separate combinations known only to them.