Porto-Novo is the capital of Benin, but all government and trade is in Cotonou. Porto-Novo is all about colonial heritage, both from the French Colonial Empire and Colonial Portugal. I recommend having your private driver drop you at the botanical gardens and make your way from there, passing all places of interest, and finish at the house of the Nine-head monster.

After exploring the Botanical Gardens first go to the central square with the statue of King Toffa I. Continue to the cathedral and make your way towards the old mosque. You’ll pass some other churches, markets, and colonial buildings. You can also visit the inside of the old mosque, but you need someone to open it. That’s why I highly recommend getting a local guide who can show you all and more places of interest. I saw more as I expected. From the old mosque it’s a short walk to the Nine Headed Monster house. Make sure your driver is there to pick you up, so you don’t need to walk back and thus save time. Have lunch in Porto-Novo at one of the local places.

I think the Colonial heritage has some UOV but it needs a lot of attention and preservation. Many buildings are falling apart and the cathedral also has had its best days. I think it's a good addition to Benins WHS list.