David is a keen walker and has done many of the long treks in Europe. See the links below:

2000 - GR20, Corsica
2001 - Tour of the Queyras
2002 - Tour of the Oisans
2003 - GR11, Coast to Coast through the Spanish Pyrenees (website) or - pictures on Flickr here
2004 - GR5 North - pictures on Picasa here
2005 - GR5 South - pictures on Picasa here
2006 - Alpine Pass Route
2007 - Tour of the Queyras and Monte Viso - pictures on Flickr here
2008 - Tour of the Oisans
2010 - Tour of the Auvergne

Also UK Coast to Coast and West Highland Way.