Timeline of attendees

I have a table which shows a list of attendees with a coded 'reason for attendance' using a countif formula. I also have the time they came in and time they left. I am stuck trying to display this information visually and could really use your help. What I would like to achieve is a timeline with little bars spanning over the time the attendees were at the event. This would help show busy times etc.

It has been a while since I used excel (or any spreadsheet), so would really appreciate your help in working this out!

Thanks in advance!

Thanks for the link! That is precisely what I am trying to achieve. However, the events are all overnight, so they go before and after midnight. How do you advise I keep that continuous? Include the dates as well?