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Welcome to the Witness History Podcast from the BBC World Service.

Today we're telling you the remarkable story of how a guide dog named Reselle

helped save the life of her blind owner during the 9-11 attacks.

In 2017, Simon Watts spoke to the man she saved.

On the morning of September 11, 2001, Michael Hingson was on the 78th floor of the World Trade Center.

He was working as the office manager for a data storage firm.

We had planned to conduct four sale seminars that day.

50 people coming in in the course of the day and we had food arranged for them.

Reselle was asleep under my desk.

I was reaching for a stationery to create a list of all of the people who were attending the seminars.

When we heard a muffled thump or explosion,

and then the building began to literally tip in one direction,

and the building actually tipped about 20 feet before it stopped and came back to its regular position.

We had no idea what happened.

In fact, the 9-11 hijackers had flown one of their airplanes into the North Tower of the Trade Center,

20 floors above Michael's office.

His colleague David Frank began to describe what he could see.

David looked out the window and saw things falling outside the window and started shouting,

oh my god, Mike, there's fire and smoke above us.

...