(Updated 8:05 a.m. EDT) -- Most cruise lines have voluntarily suspended their operations until the end of April, and in some cases further out.

A few weeks ago, when operations were initially suspended in Asia, Royal Caribbean redeployed its China-based ships to Australia offering free cruises to first responders who battled the country's bush fires.

But now that virtually all cruising has ceased and ships are either docked in ports around the world or idling at sea, what are lines doing with them?

Carnival Corporation and Saga Cruises, have offered to turn their fleets into floating hospitals; while American Queen Steamboat Company and Victory Cruise Lines have offered their fleet to house quarantined U.S. military personnel.

Other lines, including Celebrity Cruises, have allowed crew "upstairs" to see how passengers live.

Here is a glimpse of what cruise lines are doing with their empty ships.

American Queen Steamboat Company & Victory Cruise Lines

AQSC and Victory Cruise Lines are in talks with the Federal Government to explore ways in which their ships could house quarantined miltary personnel.

A statement from the line read:

"American Queen Steamboat Company (AQSC) and Victory Cruise Lines (VCL) are currently exploring ways to work with the US Federal Government for their usage of our vessels. The vessels would house US Military personnel that are under quarantine, as they have either arrived from a foreign country or will be departing shortly for a foreign country.

"Cities where the AQSC and VCL vessels could potentially be stationed include Seattle, San Diego, St. Louis, New Orleans, Norfolk and Miami. AQSC and VCL would be pleased to assist the Federal Government during this crisis, and our six vessels are readily available and on standby."

Carnival Corp.

The world's largest cruise brand, which includes lines like Carnival Cruise Line, Princess Cruises, Holland America Line and P&O Cruises, offered to turn its fleet into floating hospitals on March 19.

Sky  Princess   # We Will Be Back
Princess Cruises: Princess Cruises sent out a positive message -- one that was entirely crew-led," when workers onboard Sky Princess spelled out "#WeWillBeBack" in cabin lights.

The line is also calling at Princess Cays for crew to enjoy the private island and allowing all crew to use the main pool deck. 

Holland America Line: What started with five HAL ships anchored around Grand Bahama Island sounding their horn has now extended to other lines.

HAL's Instagram account states: "Each night at 7:30 p.m. ET, all of the ships anchored around Grand Bahama Island -- including five HAL ships -- are sounding their horns at the same time in solidarity, letting the world know that we are strong, safe and healthy onboard, and we are thinking of everyone. #HopeFloats"

Celebrity Cruises' Captain Kate McCue, currently in-command aboard Celebrity Edge, shared a video on her Instagram channel commemorating the nightly event.

“On March 20th we started something special," said Captain Kate in her Instagram post. "With ships from different companies congregating in the same "neighborhood" it was a perfect opportunity to celebrate our solidarity. As a sign that we're all in this and we'll get through it together, we invite all ships, (currently with over 250,000 crew members onboard around the globe), to join in a horn salute at 7:30 every evening going forward.

"We sound our horns, to let our crew and the world know that while we are strong, safe, and healthy on board, we are thinking of those at home and hoping the same for them. Until our safe returns to our home ports, we wish them fair winds and following seas."

In addition, the officers and crew of Rotterdam came together to thank medical professionals and first responders who are working around the clock, in a tribute onboard the ship.

Carnival Cruise Line: Carnival is lighting up all its ships with the "We Will Be Back" message. The process of figuring out which cabins to light up required a coordination between land operations and those at sea, according to Stephan Christoffersson, the company's vice president of housekeeping.

In Australia, the poignant promise lit up Carnival Spirit, docked opposite the Sydney Opera House, which is now closed.

"The crew takes a great deal of pride in their jobs, and this project in particular has extra important meaning to them," he said. "More than anything our crew members want everyone to know that they are doing well and can't wait to get back to the business of creating memories."

Azura  We'll  Meet  Again

Heart NHS P&O Cruises Britannia

P&O Cruises: British cruise line P&O Cruise lit Azura off Barbados to say "We'll meet again" while flagship Britannia lit up with the message "#Love NHS" in Southhampton, in support of the U.K.'s tireless health workers.

Seabourn: Seabourn Encore, which is currently off the coast of Freemantle, Western Australia, created a heart-shaped ship track in the ocean.

Royal Caribbean Cruises Ltd.

The brand, which encompasses Royal Caribbean, Celebrity Cruises, Azamara and Silversea, is giving their hard-working crew an opportunity to experience spaces usually reserved for guests. 

On Silhouette, for example, Hotel Director Jamie Petts told Cruise Critic, which was onboard for the ship's last sailing before the shutdown, that the crew mess would move to the Ocean View Cafe and the main pool deck would be open to crew as a recreation area.

On Celebrity Edge, Captain Kate McCue told crew they would all be moving to balcony cabins. And some crew members were even upgraded to suites thanks to a random lottery.

On Royal Caribbean's Oasis of the Seas, casino host Chris Wong has been vlogging, showing what daily life looks like. In one video, you can see him and a co-worker enjoying a meal together at specialty restaurant, Chops -- a spot usually reserved for paying passengers.

Marella Cruises

Captain Jason Ikiadis of Marella Discovery 2, after dropping passengers off at Montego Bay, Jamaica, then went back to sea to "draw" a Tui smile in the ocean -- measuring 12 nautical miles high and 16 nautical miles wide. He said: "Myself, First Officer Cosmin and our bridge team worked together to trace the TUI smile as we wanted to do something that would make both our customers and teams smile as a thank you for supporting us during these unprecedented times.

"We'll be ready and waiting to set sail with our customers soon."

MSC Cruises

The MSC Group has converted one its ferries, MSC Splendid, into a floating hospital.

The crew of MSC Grandiosa lit up the side of the ship with the Italian words: Andra Tutto Bene – "Everything Will be Fine".

Saga Cruises

U.K.-based Saga Cruises has offered its two ships, Saga Sapphire and new-build Spirit of Discovery, as medical centers, from March 20.