What physical features of would make an overland journey from rome to London difficult?

An overland journey from Rome to London would be challenging due to several physical features. The rugged terrain of the Alps presents significant elevation changes and difficult weather conditions, while the marshy lowlands in northern Italy and parts of France can hinder travel. Additionally, the dense forests and river systems in regions like the Rhône Valley and the Seine can complicate navigation and transport. Finally, the varying climates and potential for harsh weather across the journey could further impede progress.