I'm a apprentice!

Spain <-> France [on foot -Puigcerdą-Bourg Madame-, by bus, by train, by car]
Spain <-> Andorra [on foot one way only, by bus, by car]
Switzerland <-> France [on foot -Basel & Geneve-, by car, by train]
Switzerland <-> Italy [on foot -Como>Chiasso-, by bike, by train]
Switzerland <-> Lichtenstein [by bus]
Italy <-> Vatican [on foot]
Italy <-> France [by train]
Italy <-> Austria [by bus]
Italy <-> Greece [by ferry -Brindisi>Patras]
Germany --> Czech Republic [by train one way]
Austria <-> Czech Republic [by bus, by train one way]
France <-> UK [by train -eurotunnel]
France <-> Belgium [by train]
France <-> Germany [by train]
Belgium <-> Netherlands [by train]
USA <-> Canada [on foot -Niagara]