About 30 minutes
Make sure to get tickets online and go on the hike after wards.
The tour is roughly about 40 minutes depends on the tour guide and number of visitors streaming into the place. On a busy day it can be shorter. You always want to make advanced reservation on their website, pay for the tickets. And make sure you arrive 10 to 15 mimutes before the scheduled tour, simce you may have to wait for a parking spot close to the entrance. The place is always jam packed over the weekend and in major holidays.
But need to wait in a regular holiday. You can get tickets online too. That will be better
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