It is a vast ship boasting a crew of 2,100 crew. It can host 6,780 guests.
From a plant lover's perspective, the Harmony of the Seas takes parks and gardens to a new level. On board there is an impressive 10,587 plants, 48 vine plants, and 52 trees.
I'm supposing that there are also huge beds and borders with soil and compost deep enough to support the roots of these plants?
What a great initiative. Imagine sitting under the shade of a tree as this vast boat crosses the equator. Pretty unique, I would assume.
But what about bio security? In today's ever challenging environment, growers and gardeners are constantly warned of the risks of contamination to our native plants from pests and diseases hosted on plant matter imported from abroad.
The vessel, owned by Royal Caribbean, will spend its life travelling the high seas, docking at exotic locations around the world. Every time it docks there's the potential for a parasitic threat - whether that's an insect or a pathogen - to be passed from shore to ship, and vice versa. Any potential contamination then has the ability to go wherever the ship goes.
Under normal circumstances one would imagine insects and bacteria dying very quickly without a suitable host. For example if a ship's guest wandered around a park or garden in Egypt, any pathogen picked up on a shoe is likely not to survive without a suitable host to incubate it.
But if any pathogen, during its transit from shore to ship, has an opportunity to jump onto a suitable host i.e. a tree or plant, then there's a possibility that that pathogen will thrive on its new host.
I can see many opportunities for potential plant diseases to reach land, at many ports of call, and infect local flora and fauna.
Defra publishes advisory information on the transit of plants into the United Kingdom.
DEFRA says: Plant health legislation controls the import and movement of certain plants, seeds and organic matter - such as soil - and certain plant products, including fruit, potatoes, vegetables, cut flowers, foliage and grain.
Controls differ according to the species - and whether or not they are classified as quarantine organisms - but could include the need for classification, a phytosanitary certificate, a plant passport and/or inspection requirements.
There are two main elements of plant health control relevant to growers and crop farmers:
protection against quarantine organisms - measures to prevent the introduction and spread of harmful plant pests and diseases which are not established in the European Union
certification - ensures that high-quality planting material which is free from specific pests and diseases is available to growers
DEFRA is very clear that plants, soil and seedlings from all non-EU countries is tightly controlled or strictly forbidden.