Abstract: The novel invention relates to ladders, especially lean-on ladders. It is proposed to equip ladders with a positioning support at the production stage or as additional means such that, according to the particular use of the ladder in each case, it can be positioned and used safely and without causing damage with a lean-on or positioning element for flat walls, for example even for glass surfaces, or internal/external corners where walls meet, and even for relatively large columns. The invention makes it possible--with a level of security against accidents not possible hither--to work on a ladder without causing damage to building structures, vehicles, aircraft, ships and furniture.