Eukaryota

The domain Eukaryota includes all organisms that have nuclei that contain their genetic material.

Some of organella? of Eukaryota cells, most notably Mitochondrion and Chloroplast, have double membranes. They are widely belived to be Endosymbionts. Nucleus also have double membrane, but it's usually not considered to be Endosymbiont.

Eukaryota cells are much bigger than Prokaryota?. Volume difference is of order o magnitude of thousand times.

Eukaryota is the youngest of three domains.

This includes four out of the five older "kingdoms" from Linnaean taxonomy,

Protista -- Fungi -- Plantae -- Animalia