The prediction window was 60 minutes with an additional 30 minutes

The image uses three basic colours: red, yellow and black. The same colors of the Belgian flag.

Red and yellow specifically are the colors of the flag of the Belgian city, Ostend.

Ostend's Coat of Arms features a V shape surrounded by three keys. The V shape is reversed and the opposite of a key is a keyhole.

The illustration of Agatha Trunchbull from the Roald Dahl novel, Matilda, can be linked to a statue in Ostend known as Fat Matilda. Matilda can also be spelled as Mathilde. Searching in Google for Ostend and Matilda suggests the statue.

Also of note is a popular Belgian restaurant across the road called Bistro Mathilda. The name “Mathilda” refers to the famous sculpture by famous Belgian sculptur, George Grard, that is entitled La Mer (“The Sea”), also called “De Dikke Mathile” (meaning “fat Mathilda”) by the locals.

Locating the portal gives the name "Dikke Mathille (Fat Mathilda) Ostend", however as the image file's data suggests no(english), the English part should be removed, giving us just "Dikke Mathille Ostend", the correct passcode.

Lastly, reversing the fish-human-legs would suggest a mermaid (human top, fish bottom). However, La Mer is not a mermaid, so it may be suggested that the images of the fish-persons are literally a red herring, which is the type of fish shown, thus designed to mislead decoders.

The passcode to get this Tessera was DikkeMathilleOstend