Answer the following question given this paragraph: 

Old Faithful ( Figure below ) is the best-known geyser in the world. The geyser erupts faithfully every 90 minutes, day after day. During each eruption, it may release as much as 30,000 liters of water!.


Q: What is the nickname of the best-known geyser in the world, which erupts reliably every 90 minutes?


A:
old faithful