Over the following days the Trekker captured imagery of the river as it wound through Slovakia, Croatia Serbia, Hungary, Bulgaria and Romania.
Budapest from the ms Treasures. Photo: Google
This shallow, marshy, lower section of the 1, 794-mile long river is not hugely scenic when compared with Austria's Wachau Valley further north, but highlights of the footage here include the imposing Bratislava Castle (Slovakia), the Chain Bridge and Hungarian Parliament Building in Budapest (Hungary) and the Franciscan Monastery and Church of St Philip, in the Croatian city of Vukovar.
Bratislava from the river. Photo: Google
The rock sculpture of Decebalus, a 40-metre high carving of a king who fought Roman emperors for the independence of his country, is also captured in the panoramas, at the Iron Gates on the border of Romania and Serbia.
The Trekker creates a 360-degree panoramic view aided by 15 individually-angled lenses. The views captured by the lenses are then digitally stitched to create a full panorama.
Viewers can change their viewpoint up, down, left and right by moving their mouse – an effective tool for viewing the ship's interiors, as well as the scenery.
There are no "Hello Mum" moments. Tauck said ensuring the passenger experience wasn’t impacted was a prerequisite for the project, so the camera was positioned in an area of the ship inaccessible to them.
The river in the Coronini area. Photo: Google
For those keen to see inside a rivership, the Trekker also captured 360-degree views of the ms Treasures’ Compass Rose dining room, Panorama Lounge and Sun Deck. Other scenes captured from on board span six countries, from Bratislava and Slovakia to Cernavoda in Romania, illustrating the diverse nature of a river-cruise holiday.