Calicheamicin is a natural product with antitumour properties discovered in the 1980s, with the structure shown below. As noted elsewhere, this structure has many weird properties, including amongst other features an unusual “enedidyne” motif and the presence of an iodo group on an aromatic ring. Its isolated 3D structure is quite difficult to get hold of (embedded structures in a DNA fragment are available however); the 3D model associated with the Wikipedia entry is essentially only in 2D. The representation shown below, including the absolute stereochemistry, was obtained from the SciFinder entry.