Is there any programme more likely to disappoint with the glaring disparity between what's promised and what really happens than Timeteam?
Show after show, you are tantalized with all sorts of wonderfully exciting things, yet all they ever find are some foundation post holes and an old fireplace. Indiana Jones it is not.

One thing that I have always found exciting and mysterious though is the appearance of crop marks , only visible from the air, revealing all sorts of hidden things (which of course turn out to be a fireplace and some post holes). Much of the chance of seeing these palimpsest lies in the crop being grown. From the blog BLDBLG:

Field archaeologists know that vegetation grows differently on soil that has been disturbed, even if that disturbance happened centuries ago. They know that crops grow more luxuriantly over silted-up ditches, and more stunted where there are buried remains. The site of a Roman villa might go unnoticed until a field of wheat grows and ripens, to reveal most strangely the outlines of buried masonry, only to disappear again at harvest. Slight contours or indentations on the land marking out the site of a lost settlement might be invisible to the eye until a low sun throws them into sharp but momentary relief.

Barley is a more sensitive ‘developer,’ for example, than oats, wheat, or grass, but only in certain soils. Dry spells can bring about remarkably sharp crop sites.

One of the most remarkable things about aerial archaeology is that very few human processes will completely remove a site from view for ever. It might be decades—centuries even—before the right combination of crop growth, rain, sun, and aerial observer results in a site manifesting itself and being photographed. But unless deep excavations or quarrying are carried out, removing all traces of the site, the possibility remains that one day, under new conditions, it will reveal itself.