Solid Hardwood, Engineered and Laminate Flooring - Problem areas in a parquet floor

I have parquet wood tile flooring in my 20 year old house. One spot near a back door has dark stains from something that seeped into the wood grain. It may be the previous owner had a pet that wet a small rug in front of that door. it doesn't smell but is unsightly if I don't cover it with a rug.

Will anything clean it? I'm thinking of selling and wondering how to best spruce up this parquet floor? (Wish I had replaced it when I first moved in). There apepars to have been some slight shrinkage around certain edges and especially doors so has some slight cracks between tiles I'd like to address somehow too.

Thanks!

You may can sand off the finish and daub some bleach on the area to lighten it up a little. If that works, then you will need to restain and spray some polyurethane over it in several coats.