A 3-day, 2-night trip to Ho Chi Minh City and the Mekong Delta would allow you to experience the vibrant culture and rich history of southern Vietnam.

In Ho Chi Minh City, also known as Saigon, you could visit iconic landmarks such as the Notre Dame Cathedral, the Central Post Office, and the Reunification Palace, as well as shop at local markets and sample delicious Vietnamese cuisine.

From Ho Chi Minh City, you could take a day trip to the Mekong Delta, a region known for its vast network of rivers and canals, as well as its abundant agriculture and traditional villages. There are many options for touring the Mekong Delta, including boat rides through the waterways and visits to local markets and handicraft villages.

On the third day, you could spend some more time exploring Ho Chi Minh City or take a day trip to nearby attractions such as the Cu Chi Tunnels, a network of underground tunnels used by the Viet Cong during the Vietnam War.

Overall, a 3-day, 2-night trip to Ho Chi Minh City and the Mekong Delta allows you to experience the best of what these destinations have to offer, from the bustling city life of Ho Chi Minh City to the peaceful and picturesque scenery of the Mekong Delta.