I loved reading about and seeing the wonderful pictures from your surprise trip to Belfast. What an amazing birthday present! :)
It does indeed look like you had some cold weather, but I'm glad it was dry. Like David mentioned, if you get the chance next time, make sure to go up to Belfast Castle and Cave Hill. It's a lovely hike, and you get an amazing view of the city from up the mountain.
I'm so glad you enjoyed Crumlin Road Gaol as well, as it's one of my favourite places in the city too. I hope I get to go on one of their Halloween tours in the future. Apparently they have a few 'house ghosts', and one of them resides in the tunnel you mentioned.👻
Is there anything else in the city you'd like to see during a possible future trip? There are also a lot of lovely places just outside of the city, like for example Belvoir Forest Park
. I've added a picture of the beautiful meadow there, and highly recommend it for a stroll during the warmer months. :)