A lavish private palace in Ealing, a converted Victorian terraced house in Hackney, and one of the City's most iconic landmarks, 30 St Mary Axe (aka the Gherkin) are among the buildings that will be revealing their secrets to visitors during London's forthcoming Open House weekend. Celebrating its 20th anniversary, this year's event will be the biggest yet, with more than 750 buildings opening their doors alongside a programme of neighbourhood walks, cycle rides, night-time openings and experts' talks – all for free – on 22 and 23 September.
openhouselondon.org.uk

Travel clinic

The dilemma My friend and I enjoyed a fabulous trip to New England to see the autumn colours last year. Is there anywhere closer to home where we can see a similar display? Kate, Canterbury

No need to cross the Atlantic – the beautiful Engadine valley in Switzerland puts on a spectacular show of colour as the larch trees turn from green to gold in September and October, enhanced by the reflection in the region's crystal-clear lakes and the spectacular Alpine backdrops.

The three-star Hotel Meisser is a cosy family-run retreat with wood-panelled rooms, mountain views and hearty food (the half-board option is great value) in the attractive village of Guarda (+41 081 862 2132, hotel-meisser.ch; doubles from €90 a night). There are some beautiful hikes from the doorstep, but if you wish to explore further afield, a Flexi Pass (swiss-pass.ch) will give you unlimited journeys on the Swiss rail network – a wonderful way to soak up the autumn colours.

From the station at Guarda you can connect to several classic rail journeys, including the Glacier Express, which runs from nearby St Moritz to Zermatt. BA has return flights from London to Zurich from £135 in September.

Three of the best luxury treehouses

Forget the knee-scraping treetop dens you may have played in as a child. Offering the style and comfort of a five-star hotel, these new sylvan retreats scale the heights of holiday luxury

Cleveley Mere, Lancashire
A slick waterside retreat that comes with its own rope bridge, pier and boat. Sleeps four. From £219 a night. cleveleymere.com/tree-house.php

Bagthorpe Treehouse, Norfolk
Leafy luxury, four-poster bed and copper bathtub. Sleeps four. From £215 a night. canopyandstars.co.uk/bagthorpe-treehouse

Chewton Glen, Hampshire
The five-star hotel has opened six new suites on stilts that include outdoor hot tubs. From £600 a night. chewtonglen.com/tree-house-suites