Crystal's ocean ships are quite large for our 'Best of the Best' category, carrying up to 848 (Crystal Symphony) or 980 (Crystal Serenity) guests. Rest assured that, once on board, you will feel as if you are somewhere intimate and personal, with lots of small restaurants and bars, all with the personalised style of service you would expect in a boutique hotel.

The food is amazing, and the chefs have worked hard to introduce a range of unusual and exciting Modern Cuisine dishes alongside the classic menu, making for a memorable dining experience, in whichever of the various restaurants you choose to dine.

The advantage of having so much space is evident in the range of facilities on board, and the extensive and stimulating programme of activities. Entertainment is more varied, and of a higher quality, than you would normally expect on a ship of this standard.

Even the most restless traveller will find plenty to do on a Crystal ship during sea days, whilst itineraries are planned to feature plenty of overnights in port, with a varied and interesting range of shore excursions to suit all tastes.

Worth noting is that a low-key children's programme makes this line the ideal choice for families during holiday time - but there is sufficient space to ensure a child-free environment for those who prefer it.

The launch of Crystal River Cruises in 2016 has well and truly raised the bar when it comes to river cruising; there is simply no other river cruise line in Europe right now that can match the ambition and the onboard delivery of Crystal.

Further developments include the launch of a new polar-class expedition yacht, Crystal Endeavor, in 2021, with two sister yachts to follow; the return of Crystal Mozart to the river fleet in 2022; and three Crystal Diamond Class ocean ships, with the first due to arrive in 2022.

Crystal Cruises are committed to developing plans for preventing pollution, complying with worldwide environmental regulations, and continually improving their environmental management system to minimise and reduce the environmental impact across their entire fleet.

Crystal have a partnership with the California Ocean Alliance and are members of ORCA's OceanWatch Programme, both of which collect scientific data about animal behaviour and best conservation practices to aid in its research and preservation efforts. On board there is a comprehensive recycling programme including involvement in the 'Clean the World Initiative' which recycles soaps, shampoos, lotions and other hygiene products to be distributed to areas of need. Water consumption has been reduced with low flow showerheads, reduced laundry and an eco-friendly filtration system to replace bottled water. Crystal have also minimised use of plastics on board.