The Seven Sisters chalk escarpment formed 100 million years ago when microscopic marine algae compressed into layers of pure white calcite, exposed by millennia of wave erosion along the East Sussex coast. The formation stretches 22 kilometres between Seaford Head and Beachy Head, with seven distinct peaks rising between 85 and 162 metres above sea level. Victorian geologists mapped the cliffs in the 1840s, documenting the continuous chalk stratum that extends beneath the Channel to mirror formations on the French coast near Dieppe. Seven Sisters Country Park occupies 280 hectares of downland, river valley and shingle beach at Exceat, designated in 1971 to protect the undeveloped coastline from urban sprawl. The Cuckmere River meanders through the park in looping oxbows, its original course straightened in the 1840s for flood control while the natural meanders remain visible from the cliff paths. The park receives 350,000 annual visitors, with foot traffic concentrated on the 13-kilometre clifftop trail that connects Seaford Head to Birling Gap. The chalk grassland supports 37 species of butterfly and rare orchids including early spider orchid and fragrant orchid, which bloom May through July. Brighton developed as a resort town in the 1750s when Dr Richard Russell published his treatise on seawater's curative properties, transforming a fishing village of 2,000 into a fashionable spa destination. The Prince Regent commissioned John Nash to design the Royal Pavilion in 1815, its Indo-Saracenic domes and minarets rising above Regency squares and crescents that housed London's seasonal elite. The London to Brighton railway opened in 1841, reducing travel time from eight hours by stagecoach to 90 minutes, democratising coastal access for the Victorian working class. Brighton Pier opened in 1899 as a landing stage for pleasure steamers, later converted to an amusement pier with a 1,722-seat theatre. The seafront spans 8 kilometres from Hove Lawns to Brighton Marina, with 5 kilometres of intact Victorian ironwork balustrades along the promenade. Coach tours departing London reach Seven Sisters Country Park in 90 minutes via the A23 and A27, arriving at the Exceat visitor centre car park where the clifftop trail begins. Most Brighton and Seven Sisters day trip from London itineraries allocate two to three hours for the cliffs walk before continuing 13 kilometres west to Brighton for afternoon exploration of the Lanes, pier and pavilion. The dual-destination format emerged in the 1990s as tour operators sought to combine natural landscape with urban heritage in single-day offerings from the capital.